Sperm morphology: assessing the agreement between the manual method (strict criteria) and the sperm morphology analyzer IVOS

OBJECTIVES

To correlate the percentage normal morphology reported by different observers and a computerized method (IVOS; Hamilton-Thorne Research, Beverly, MA) on a slide-by-slide basis using strict criteria: [1] Experienced observer (T.F.K.) versus experienced observer (R.M.), [2] experienced observer (T.F.K.) versus sperm morphology analyzer (IVOS), and [3] repeatability of normal and abnormal cells (IVOS). DESIGN SETTING, PATIENTS: Slides from 30 different patients from the Tygerberg IVF program were selected randomly. Microscopic fields and sperm cells were chosen randomly and percent normal morphology was recorded (objectives 1 and 2). The same slides were used and a cell-by-cell repeatability was done as outlined (objective 3).

RESULTS

Experiment 1 (objective 1): there was no significant bias between T.F.K. and R.M. The limits of agreement were 8.6% and -7.3%. The SDs were not significantly different (P = 0.1283). The Spearman correlation coefficient between readers was 0.83. Experiment 2 (objective 2): the same findings were reported but the limits of agreement were 12.1% and -15.5%. The Spearman correlation coefficient was 0.85. The limits of agreement was tighter below 20% normal forms (+8.4 and -6.6). Experiment 3 (objective 3) (repeatability): 255 cells were analyzed three times in succession. Estimating pairwise agreement, the kappa statistic for the pairs are 0.85, 0.80, and 0.85, respectively, which compares favorably with the second canonical moment of 0.8329 (kappa = 0.83).

DISCUSSION

The computer's ability to classify normal morphology per slide is promising. Below 20% normal forms, the limit of agreement is tight. Because of the 6% higher reading compared with the manual method, different thresholds possibly will be developed to identify subfertile from fertile patients. The computer gives excellent repeatability of normal and abnormal cells. Based on results obtained, this system can be of clinical value both in IVF units and andrology laboratories but more clinical data is required in this field.

The haematological profile of urban black Africans aged 15-64 years in the Cape Peninsula

A stratified probability sample (n = 986) with quotas was drawn from black residential areas in the Cape Peninsula, South Africa. Subjects (n = 819) aged 15-64 years, participated in a coronary heart disease (CHD) risk factor survey, the BRISK Study. Nutritional status and prevalence of CHD was determined in this population undergoing rapid urbanization. Full blood and differential white blood cell counts provided data to calculate population reference values based on the 95% reference limits of the haematological parameter. Mean haemoglobin concentrations (Hb) in men (14.0 g/dl) and women (12.4 g/dl) were +/- 1.5 g/dl lower than previous South African reports. Mean BRISK Hb values were very similar to the World Health Organization's Hb cutoff criteria (< 13 g/dl men; < 12 g/dl women), indicating a possible high prevalence of anaemia. Significantly higher (P < 0.05) mean values for red cell indices were confirmed in men, which also reflected equally higher red blood cell counts (RBC), haematocrit (HCT) and mean corpuscular haemoglobin (MCH) values. Mean Hb values were significantly lower in the younger (15-24 years) and older (55-64 years) men compared with 25-54 year-olds (P < 0.05). Hypochromic microcytic anaemia was more prevalent in women, possibly due to iron deficiency (ID), while macrocytic anaemia was more prevalent in men. No significant differences were noted in mean total and differential white blood cell counts (WBC) between men and women.(ABSTRACT TRUNCATED AT 250 WORDS)

Smoking in the black community of the Cape Peninsula, South Africa

The purpose of this study was to determine tobacco-use and related factors in the black population of the Cape Peninsula. About 52% of the men, but only 8% of the women used tobacco regularly. Men and women who smoked cigarettes, smoked 9.6 and 4.3 cigarettes on average per day, respectively. Although many men smoked, 80% perceived smoking to be harmful to health as did 92% of the women. For women, smoking was inversely related to their level of education, while for men it was directly related to being employed. Smoking was also related to the use of alcohol in both genders. Women below 45 years who had spent less than a third of their lives in the city had lower smoking rates than those who had spent more than a third of their lives in the city. Smoking is one of the most important public health issues facing the black community of the Cape Peninsula.

Assessment of alcohol-screening instruments in tuberculosis patients

SETTING

Two samples of hospitalised tuberculosis (TB) patients were randomly selected.

OBJECTIVE

To evaluate the usefulness of two alcohol-use screening instruments (AUDIT and CAGE).

DESIGN

A cross-sectional analytic study was conducted with 122 patients (61 Coloured and 61 African).

RESULTS

In the coloured group, AUDIT and CAGE identified 57% and 62% of patients respectively as scoring above the cut-off points for possible alcohol misuse. In the African group, AUDIT and CAGE identified 36% and 31% of patients respectively as scoring above the cut-off points. Rates for risky drinking found in community-based studies were lower than those found in this study for the Coloured sample. The male African group's CAGE result for alcohol misuse (17/46; 37%) is similar to the CAGE finding for African male mineworkers (33%), also findings from a community study in African males (34-37%). Both instruments were in agreement with each other for both groups. Slight to substantial agreement was observed between the instruments and other assessments of alcohol misuse (ward sister's perception, patient's file, self-perception and communal drinking), as well as between these assessments, for both groups.

CONCLUSION

Screening instruments such as AUDIT and CAGE can play a useful role in describing alcohol misuse among TB patients and in facilitating intervention programmes.

Development of a predictive model for optimal zona pellucida binding using insemination volume and sperm concentration

OBJECTIVE

To develop a predictive model under hemizona assay (HZA) conditions for human spermatozoa concentrations and insemination volume for optimum zona pellucida (ZP) binding.

DESIGN

Analysis of 20 different insemination volumes for zona binding and sperm morphology under HZA conditions.

SETTING

Reproductive biology unit, tertiary medical center.

PATIENTS

Four proven fertile sperm donors.

MAIN OUTCOME MEASURES

5-, 20-, 50-, 80-, and 100-microL droplets were analyzed with four different concentrations of 0.5 x 10(6), 1.0 x 10(6), 2.0 x 10(6), and 4.0 x 10(6) cells/mL to determine the number of sperm bound to each hemizona. Fifteen hemizonae were used for each insemination volume or microdroplet. Response surface regression model with volume and concentration as the regressor variables has been used.

RESULTS

The response surface of binding for the factors concentration and volume showed nonlinear association. A formula, indicating the optimal sperm insemination volume for maximum sperm binding to the ZP, Vmax = -(b1 + b5c)/2b6c, is described. The transformed data indicated 60 microL containing 4 x 10(6) sperm/mL to be optimal. Although morphology of zona spermatozoa is superior compared with seminal and postswim-up samples, no difference among the percentage of the normal morphology in different microdroplets could be demonstrated.

CONCLUSION

Optimal volume for the obtained concentration of spermatozoa from a patient can be calculated and therapeutically used for cases of severe oligozoospermic patients by microvolume inseminations in IVF practice.

Induced acrosome reactions as fertility predictor

PURPOSE

This study was conducted to determine the fertility predictive value of acrosome reaction rates and indices (induced minus control) of human spermatozoa. By comparison these outcomes with in vitro fertilization success. The effect of oocyte-cumulus complex exposure on the induction of the acrosome reaction was also analyzed. Patients attending our assisted reproduction unit for infertility treatment were included in the study. Acrosome reactions were determined on ethanol-permeabilized smears using FITC-conjugated Pisum sativum agglutinin. The acrosome reaction inducing agent used was calcium ionophore A23187 (10 microM/ml).

RESULTS

Poor correlations were found between all the acrosome reaction rates and indices and in vitro fertilization. The presence of oocyte-cumulus complexes had no effect on the spontaneous acrosome reactions, but had a significant effect on the inducibility of the acrosome reaction. Exposure to oocyte-cumulus complexes resulted in the mean percentage sperm induced to be 7.8% (SE = 3.1%) higher compared to the control samples.

CONCLUSIONS

Acrosome reaction rates and indices were therefore found to have no significant value in the prediction of male fertility and/or in vitro fertilization success. This study did, however, show that exposure to oocyte-cumulus complexes significantly increases the inducible sperm population.

Selective capacity of glass-wool filtration for the separation of human spermatozoa with condensed chromatin: a possible therapeutic modality for male-factor cases?

PURPOSE

The aim of this study was to evaluate chromatin condensation of human spermatozoa following swim-up compared to glass-wool separation. Semen aliquots from men attending an andrological outpatient clinic were processed by means of a swim-up procedure and glass-wool filtration. Chromatin condensation was recorded using aniline blue staining and results were reported according to color intensity of stained sperm heads. Morphometric measurements of sperm heads were performed on stained sperm samples.

RESULTS

Glass-wool filtration resulted (i) in a significantly higher total motile sperm count (P < 0.0005) compared to swim-up and (ii) in a significantly higher percentage of normal chromatin-condensed spermatozoa compared to the ejaculate (P < 0.01).

CONCLUSION

In contrast, comparing swim-up to the ejaculate, the percentage of matured nuclei (unstained spermatozoa) retrieved following swim-up was significantly lower (P < 0.005). Glass-wool filtration separates human spermatozoa according to motility and size of the sperm head. The size of the sperm head closely correlated with the chromatin condensation quality.

Risk factors for the development of osteoporosis in a South African population. A prospective analysis

Despite the vast number of risk factors that apparently predispose to the development of osteoporosis (OP), they have not been accurately identified and given relative priority. In order to analyse possible risk factors prospectively in a local patient population with overt OP (histomorphometrically confirmed and characterised) and compare it with an appropriately matched non-OP control group (with normal bone mass on dual-energy X-ray absorptiometry), a detailed general history, risk factor analysis, dietary history and anthropometric data were obtained from 56 OP and 125 non-OP subjects. In females a positive family history of OP (P = 0.002), a fair complexion (P = 0.009), lower body mass (P = 0.02) and height (P = 0.03), no breast-feeding of babies (P = 0.006), a history of smoking (P = 0.001) and fat distribution around the waist (P = 0.009) were identified as risk factors. In males lack of exercise (P = 0.008), a history of smoking (P = 0.01), lower body mass (P = 0.04) and height (P = 0.04), a preference for salty food (P = 0.02) and fat distribution around the waist (P = 0.002) appeared to predispose. Dietary calcium, phosphorus, protein and caffeine intakes were similar in OP and control subjects, but alcohol consumption was clearly higher in both OP males (P = 0.001) and females (P = 0.01).

Free cholesterol concentrations in the high-density lipoprotein subfraction-3 as a risk indicator in patients with angiographically documented coronary artery disease

BACKGROUND

The pathophysiology of plasma lipoprotein metabolism has long been linked to coronary artery disease (CAD). The present study evaluated the association between plasma lipoprotein lipid and apolipoprotein (apo) components and CAD in a group of 80 consecutive Caucasian patients undergoing coronary angiography.

METHODS

Coronary cineangiography was carried out using the Judkins technique and the lesions quantified by calculating a coronary artery lesion score (CALS). Very low- and low-density lipoproteins (VLDL and LDL) were separated by ultracentrifugation, and high-density lipoprotein (HDL) and HDL subfraction-3 (HDL3) isolated by a differential precipitation procedure. Apo A-I, A-II, and B were assayed by endpoint laser nephelometry using specific antibodies. Total cholesterol, free cholesterol, and fatty acid concentrations were measured by gas-liquid chromatography, and lecithin: cholesterol acyltransferase (LCAT) activity by the decrease in the concentration of free cholesterol.

RESULTS

On the basis of the presence of CAD, the 80 patients were divided into two groups: 52 (65%) with CAD (mean CALS = 7.8) and 28 (35%) without CAD (zero CALS). The lipoprotein fraction that most clearly differentiated the groups was HDL cholesterol concentration, with a mean +/- SEM value of 36.5 +/- 1.5 mg/dl for those with CAD and 45.1 +/- 2.1 mg/dl for those without (P < 0.01). The mean HDL3 cholesterol concentration was 29.9 +/- 1.2 mg/dl for patients with CAD and 37.4 +/- 1.8 mg/dl for those without (P < 0.001). These differences in HDL cholesterol and HDL3 cholesterol were mainly caused by differences in the free cholesterol component, with a mean HDL free cholesterol level of 10.8 +/- 1.1 and 16.1 +/- 1.4 mg/dl (P < 0.01), and a mean HDL3 free cholesterol level of 7.6 +/- 0.6 and 11.9 +/- 0.8 mg/dl (P < 0.001) in patients with and without CAD, respectively. Plasma LCAT activity was decreased in patients with CAD (P < 0.05), as were the apo A-I and A-II concentrations in both the HDL (P < 0.001) and HDL3 (P < 0.001) fractions. No significant association was found between CAD and HDL2 cholesterol or plasma total cholesterol, LDL cholesterol, or VLDL cholesterol concentrations. A stepwise discriminant analysis revealed that HDL3 free cholesterol was the only variable selected. Using HDL3 free cholesterol as a screening variable for CAD (cutoff 10.55 mg/dl), the sensitivity for CAD was 87% and the specificity for non-CAD 67%. The positive and negative predictive values of HDL3 free cholesterol were 82 and 75%, respectively.

CONCLUSION

We have shown that the concentrations of HDL cholesterol and HDL3 most clearly differentiated between patients with and without CAD.

Sperm decondensation and semen parameters: utilization of a simple staining technique for the evaluation of human sperm decondensation

The ability of spermatozoa to fertilize an oocyte depends on a sequence of events ending ultimately in the decondensation of the sperm chromatin on penetration of the oocyte. Knowledge of what percentage of sperm decondenses is useful, especially in patients where other functional tests and sperm quality fail to explain the reported poor in vitro fertilization (IVF) rates. The objective of this study was (1) to compare sperm decondensation induced by either SDS/EDTA or heparin with semen parameters (volume, concentration, motility and morphology), and (2) to evaluate the use of a simplified staining technique (Diff QuikR [DQ]) in comparison with the standard phase contrast method (Rose Bengal-[RB]). Randomly selected semen samples from 31 men attending an assisted reproductive programme were analysed for basic semen parameters and decondensation with SDS/EDTA and heparin. Two staining methods for the evaluation of decondensation were compared (phase contrast microscopy after Rose Bengal [RB] staining and light microscopy after Diff QuikR (DQ) staining). Moderate and grossly swollen sperm heads were recorded. Semen samples included both fertile and unfertile semen parameters. Sperm decondensation results showed poor to moderate correlations with semen parameters. The SDS/EDTA (DQ) (moderate forms) showed a significant negative correlation (r = -0.46) with seminal volume and a significant positive correlation (r = 0.41) with normal sperm morphology. The heparin (DQ) (moderate forms) decondensation showed a significant positive correlation with motility (r = 0.61) and sperm concentration (r = 0.43). The DQ method was preferred over the RB method due to its optical and storage advantage.(ABSTRACT TRUNCATED AT 250 WORDS)

Glass wool filter preparation of cryopreserved spermatozoa

Oligozoospermic and asthenozoospermic semen ejaculates, as well as cryopreserved sperm samples prepared by the wash and swim-up procedure often result in unsatisfactory sperm recovery rates. In this study the glass wool filter and the wash and swim-up preparation procedures were compared on the basis of their 'effective' (number of live sperm per millilitre) recovery rates. The glass wool filter procedure consistently produced significantly (P = 0.0002) higher viable sperm concentrations, making it the preferred method for the preparation of cryopreserved sperm to be used in assisted reproduction techniques. The use of this preparation procedure has also been shown to have no adverse affect on the fertilizing potential of human spermatozoa in our unit.

A longitudinal evaluation of the anterior border of the dentition

Posttreatment changes of orthodontically treated dentitions are inherent to every orthodontic practice. Various studies have documented the ideal posttreatment dental and cephalometric norms that could pertain to stable long-term occlusal results. Clinically, changes in these parameters are often observed as mandibular incisor crowding. The purpose of this study was to evaluate the longitudinal changes in certain variables representing the anterior border of the dentition. Eighty-eight white subjects were assessed regarding stability of the dentition after edgewise orthodontic treatment. (44% nonextraction, 56% extraction) The following variables in proximity of the anterior limit of the dentition (overbite, overjet, mandibular arch length, upper and lower incisor position, Little irregularity index) were assessed and correlated with each other. The data were subjected to descriptive statistics, the Friedman test for significant changes and pairwise comparisons, and the Spearman correlation test. Mandibular intercanine width was not significantly altered during treatment, but although not significantly, p > 0.05 did decrease beyond the original measurement during posttreatment evaluation (mean 7 years after treatment). The other variables influenced by the orthodontic manipulation were all within normal ranges and remained stable. The arch length decreased significantly (p < 0.05) during the entire evaluation period and was the only variable not stable. It was concluded that: (1) sound treatment leads to attainment of ideal occlusal parameters, (2) mandibular intercanine expansion could lead to failure of results, (3) arch length change plays a major role in causing irregularity of mandibular incisors after treatment, and (4) patient education regarding posttreatment orthodontic changes is imperative.

The hemizona assay: its role in identifying male factor infertility in assisted reproduction

OBJECTIVES

To identify male factor infertility among a group of patients in an assisted reproductive program (phase 1) and to evaluate the hemizona assay (HZA) in the diagnosis and prognosis of such a program (phase 2).

DESIGN

The IVF performance of normal gametes in the Tygerberg program were critically evaluated. Female patients were classified as pure tubal factor infertility, having a normal FSH:LH ratio on day 3 of the menstrual cycle. All participating women produced three or more preovulatory oocytes at retrieval and were inseminated with sperm considered normal by all present diagnostic criteria. The total and normal fertilization rate thresholds were defined in that group. Using those thresholds, couples tested for sperm binding in the HZA (n = 48) were used and divided into two groups according to their fertilization rates, namely group 1, low fertilization (< 55%) and group 2, normal fertilization (> 55%).

SETTING

University-based tertiary care center.

PATIENTS

Ninety-nine couples (589 oocytes) with pure tubal factor infertility and normal male factor were used in phase 1. Forty-eight couples with normal and abnormal male factors that had both HZA performed and IVF treatment were included in phase 2.

RESULTS

Investigation of the performance of normal gametes in 99 couples (589 oocytes) revealed the total fertilization rate (total number of oocytes fertilized/total number of oocytes inseminated) was (mean +/- SD) 88.6% +/- 16.8% and the normal fertilization rate (total number of oocytes with normal fertilization/total number of oocytes inseminated) was 81.3% +/- 22%. The minimum total fertilization rate that can be considered normal in the Tygerberg program using mean--2 SD is therefore 55% and for normal fertilization rate is 37%. The group with low fertilization rate (< 55%) showed a mean hemizona index (HZI) significantly lower; nevertheless, the distribution overlapping indicates a low discriminating power of the HZA. A sensitivity of 75% and a specificity of 75% were found; the positive and negative predictive values were 81% and 68%, respectively.

CONCLUSIONS

The results indicated the HZA and HZI contribute important information and can serve in conjunction with other semen characteristics as useful tools during the diagnosis of the male factor in assisted reproduction.

Raised intracranial pressure, the syndrome of inappropriate antidiuretic hormone secretion, and arginine vasopressin in tuberculous meningitis

Intracranial pressure (ICP) monitored shortly after admission over a period of 1 h in 31 children with tuberculous meningitis (TBM) was significantly higher (median 22.5 mmHg, range 8.4-50.9 mmHg) in 19 children with laboratory evidence of the syndrome of inappropriate antidiuretic hormone secretion (SIADH) than in 12 children without such evidence (median 16.2 mmHg, range 5.8-42.5 mmHg; P = 0.027). Neither plasma nor cerebrospinal fluid arginine vasopressin (AVP) was related to ICP (r = 0.33 and 0.13 respectively). Mean arterial pressure (MAP) was measured in 23 children and a moderate correlation was found with plasma AVP (r = 0.62; P = 0.0019). In TBM, plasma AVP may be secreted as a response to raised ICP in an effort to raise MAP and maintain cerebral perfusion pressure. In this setting excess fluid may be inappropriately retained, leading to hyponatremia and hypo-osmolemia.

Follicle stimulating hormone levels on cycle day 3 predict ovulation stimulation response

AIM

To determine the value of basal follicle stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) levels on cycle day 3 in predicting the ovulation stimulation response in patients receiving exogenous gonadotropins for in vitro fertilization (IVF) or gamete intrafallopian transfer (GIFT).

METHODS

One hundred eleven consecutive females with infertility due to various etiologies were investigated. Cycle day 3 serum levels of FSH, LH, and E2 were determined prior to ovulation induction with a combination of clomiphene citrate and human gonadotropins. Follicular growth was monitored ultrasonically, and when appropriate, oocytes were recruited, counted, graded, and then used, as prearranged, for either IVF or GIFT. Basal hormone levels were compared to the peak E2 concentration, the number of follicles aspirated, and the number of preovulatory oocytes recovered following drug therapy. Details of resulting pregnancies were also recorded.

RESULTS

Patients with low basal FSH levels (< 11.5 mIu/ml) yielded a higher mean number of preovulatory oocytes than those with high values (> 11.5 mIu/ml), i.e., 6.7 oocytes per cycle vs 2.5 oocytes (P < 0.001). In the low group 97% of cycles yielded more than three fertilizable oocytes compared to 42% in the high group (P < 0.5). There were 16 term pregnancies (16%) in the low group and 1 (8.3%) in the high group. Basal LH and E2 levels did not improve on the ability to distinguish between different populations of infertile females who responded differently to ovulation induction.

CONCLUSION

Cycle day 3 FSH levels are predictive of the ovulation response and probability of pregnancy in stimulated cycles and can be of value in patient selection and counseling in IVF and GIFT programs.

A new computerized method of reading sperm morphology (strict criteria) is as efficient as technician reading

OBJECTIVES

To compare the ability of a computerized method of sperm morphology with the manually recorded method in predicting in vitro fertilization (IVF) results, to compare results obtained by both methods, and to determine the intraobservation variability.

DESIGN, SETTING, PATIENTS

Forty-three stained semen slide preparations from two large level-three academic institutions' reproductive endocrinology units (IVF programs) were blindly evaluated, and the sperm were classified into normal and amorphous forms.

RESULTS

Experiment 1: Twenty-one slide preparations from the Tygerberg gamete intrafallopian transfer program were manually evaluated; the fertilization rates for the groups with < 14% and > 14% normal sperm forms were 33.3% (15/45 oocytes) and 76.6% (46/60 oocytes), respectively. Corresponding fertilization rates with FERTECH were 46.8% (30/64) and 75.6% (31/41). Experiment 2: Twenty-two slide preparations from the Norfolk IVF program were evaluated. The manual method reported a fertilization rate in the group with < 14% normal forms of 27.4% (14/51 oocytes) compared with 90.0% (127/141 oocytes) in the group with > 14% normal forms. Corresponding figures for the FERTECH method were 33.9% (18/53) and 88.4% (123/139), respectively. Experiment 3: When the 43 slide preparations were blindly evaluated using both methods, 84% of the FERTECH evaluations correlated well with the manual method and FERTECH ability to diagnose the subfertile male (< 14% normal forms) was 95% (sensitivity). Experiment 4: A total of 16 different slides (8 per group) were randomly selected and analyzed five times (100 cells per reading) by the computerized method. The slides were obtained from men with normal sperm morphology of < 14% and > 14% as classified by the manual method. In the first group (< 14%) 97.5% (39/40) of the readings classified the sperm in the proper category, whereas in the second group (> 14%) 95% (38/40) of the cases were correctly identified.

CONCLUSION

Using strict criteria for morphology evaluation, there is a positive and significant correlation between FERTECH evaluation and manual assessment. The reproducibility of the computerized method and the ability to distinguish between fertile and subfertile groups using those criteria are good.

The natural history of carcinoma of the cervix in young women

Invasive carcinoma of the cervix was treated in 1,522 patients over a 10-year period at Groote Schuur Hospital. Data for each patient included place of residence, pathological characteristics of the tumour, nodal spread, histological evidence of human papillomavirus (HPV) infection, disease stage, treatment type, treatment complications, site of recurrence and survival time. Patients aged under 35 years comprised 11.6% of the total patient group. A retrospective cohort study compared women aged under 35 years of age at the time of entry into the study and women aged 35 years or more. In all, 82 eligible young patients were compared with random sample of 82 eligible older patients. Contingency tables, life tables and proportional hazards analysis were used where appropriate. There was no significant difference across the two age groups in the incidence of non-squamous tumours, or in the grades of squamous tumours. Similarly there was no evidence of differences in lymph node involvement or HPV infection. Young patients appeared to enter the study at significantly earlier stages of the disease, and a greater proportion of them underwent surgical treatment (diff = 36.4% +/- 13.5%). In both groups treatment complications were less frequently observed after surgery than after radiotherapy. Sites of tumour recurrence were similar in both groups, and there was no apparent difference in survival times.

Effect of multiple centrifugations on the evaluation of the acrosome reaction in human spermatozoa

This study was undertaken to assess the effect of multiple centrifugations on the human acrosome reaction and in vitro fertilizing ability. Semen samples were obtained from sperm donors and from patients participating in our in vitro fertilization programme. Measured sperm samples were centrifuged twice (400xg for 5 min) before or after the induction of the acrosome reaction with calcium ionophore A23187 and before the insemination of oocytes. The samples obtained from the sperm donors were used to measure the acrosomal loss by means of indirect immunofluorescence (T6 monoclonal antibody) and the patient samples were used to assess fertilizing ability and cleavage. Samples centrifuged twice before the chemical induction of the acrosome reaction exhibited significantly elevated levels of acrosomal loss (mean = 46%) as compared to the controls (23%). However, the fertilization (P = 0.688) and cleavage (P = 0.187) rates were not significantly different between the controls and the centrifuged samples. The present study has shown that the centrifugation of motility enriched (swim-up) samples may also modify the acrosomal membrane complex, without compromising fertilizing potential.

Comparison of the effect of the amount and degree of unsaturation of dietary fat on plasma low density lipoproteins in vervet monkeys

The effects of the degree of unsaturation and of the amount of dietary fat on low density lipoprotein (LDL) concentration and composition were determined in vervet monkeys. Diets with fat contents of 41, 31 and 18% energy, each with a low and a high polyunsaturated to saturated fatty acid ratio (P/S; 0.27-0.38 and 1.13-1.47) were fed to six female vervet monkeys for two months. Another six females were given a low fat, high P/S diet for the same period of time, to serve as a reference. The cholesterol contents of the diets were low (21-33 mg per day) and relatively constant. LDL cholesterol concentrations decreased significantly (P < or = 0.01) when the dietary fat content decreased from 31 to 18% of energy. The dietary P/S ratio only affected LDL cholesterol concentrations during moderate (31% of energy) fat intake, where LDL cholesterol increased (P < or = 0.01) with a decrease in dietary P/S. Substantial individual variations were observed in LDL cholesterol concentration responses to dietary fat changes. The changes in LDL cholesterol concentrations were the result of changes in the concentration of LDL particles, as the molecular composition did not differ significantly between dietary periods. The high density lipoprotein cholesterol and the plasma triacylglycerol concentrations were not influenced by the dietary fat changes. During the high P/S diets, the percentage of 18:2 (linoleic acid) increased (P < or = 0.01) and that of 18:1 (oleic acid) decreased (P < or = 0.01) in LDL esterified cholesterol, as compared to the low P/S diets. In adipose tissue triacylglycerol the percentage of 18:2 was three times higher (P < or = 0.01) during the high P/S diets than during the low P/S diets.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of oocyte maturity in the treatment of infertility because of teratozoospermia and normozoospermia with gamete intrafallopian transfer

OBJECTIVE

To determine the effect of oocyte maturity on pregnancy rate (PR) in patients undergoing gamete intrafallopian transfer (GIFT) procedures for infertility and in whom male partners had either normozoospermia or teratozoospermia.

DESIGN

A prospective study using a combination of clomiphene citrate and human menopausal gonadotropin for ovulation induction was carried out. Five hundred thirty-seven GIFT treatment cycles were analyzed, and 423 cycles yielded four or more oocytes. Patients were divided into two groups according to the sperm morphology: those with less than 14% normal forms and those with greater than 14% normal morphology (as judged by strict criteria). These two groups were divided into a further five subcategories depending on the number of metaphase II oocytes transferred.

RESULTS

In the group less than 14% normal forms (category I; 4 metaphase I oocytes replaced), three pregnancies resulted from 33 cycles (9.09%), and in category V (4 metaphase II oocytes transferred) the PR was 15% (14/95) per cycle. In the group with greater than 14% normal forms, in category I, the PR was 16% (3/19) per cycle, and in category V, the PR was 33% (20/61) per cycle. The effect of morphology (less than 14% normal forms versus greater than 14% normal forms) on pregnancy outcome is significant (P = 0.0161). The overall effect of increasing the number of metaphase II oocytes on the pregnancy outcome was not significant (P = 0.1098). However, in the group with greater than 14% normal forms, there was a significant improvement in PR (P = 0.04) in category V.

CONCLUSION

During this prospective study, it was shown that sperm morphology plays a significant role in the pregnancy outcome in a GIFT program.

A survey of dental practice and equipment characteristics

The aim of this study was to determine what would be regarded as essential equipment required for setting up a dental practice and the cost thereof. This information could be useful for the newly qualified dentist. Seventy five completed questionnaires returned from a randomly selected group of practising dentists were analysed to obtain this information. Equipment costs were obtained from a dental supply house and are tabulated. Guidelines recommended for setting up a practice include determining the type of service to be rendered, selecting the equipment required for this purpose, seeking expert financial advice and commencing the practice on a conservative basis with only the essential items of equipment.

The Acridine Orange test: determining the relationship between sperm morphology and fertilization in vitro

The prediction of human fertilization is an important aspect of research protocols dealing with male fertility. Sperm DNA has been reported to be an indicator of human sperm fertility potential. The Acridine Orange test for evaluation of sperm DNA has been employed during the present study to determine its relationship with human sperm morphology and fertilization in vitro. Seventy-six patients from the in-vitro fertilization (IVF) and/or gamete intra-Fallopian transfer (GIFT) programme were randomly selected for the study. All patients had a routine semen analysis, sperm DNA evaluation and underwent standard IVF procedures at the time of the study. The results indicated a moderate positive correlation (r = 0.38, P = 0.0006) between results of the Acridine Orange test and normal sperm morphology. Patients with an Acridine Orange test value exceeding 24% had significantly higher oocyte fertilization rates than patients with lower values, for metaphase I (74 versus 51%, P = 0.0008) and for metaphase II oocytes (88 versus 60%, P = 0.0001). Sperm morphology, however, proved to be a more significant predictor of fertilization in vitro compared to the Acridine Orange test.

Torsion of the colon in vervet monkeys: association with an atherogenic Western-type of diet

The risk of torsion of the colon in adult male vervet monkeys (Cercopithecus aethipos) increased when they were fed with an atherogenic Western-type of diet. No cases occurred in females and rapid diagnosis is necessary to prevent lethal consequences.

Crystalluria in marathon runners. IV. Black subjects

Crystal sizes (scanning electron microscopy) and distributions (Coulter Counter) as well as 24-h urinary sodium (Na) and calcium (Ca) excretions (flame atomic absorption) were determined in a group of black South African runners immediately after a marathon and again 3 weeks later. White runners and black and white control subjects were included in the study. Particle volume-size histograms for black controls and black runners were identical. There was no significant difference in the Na excretion of all the groups. However, while urinary Ca excretion was significantly raised in white runners relative to white controls, Ca excretion in black runners was unchanged relative to their controls. It is postulated that the lower rates of urinary Ca excretion may result from lower rates of Ca resorption from bone in response to the cyclical loading of running in black marathon runners. The results of this study suggest that black marathon runners are not prone to the same increased risk of renal stone formation as are white runners.

The frontal sinus and mandibular growth prediction

The skeletal growth patterns of 103 subjects with Class I and III malocclusions were cephalometrically analyzed as advocated by Ricketts el al. to assess abnormal mandibular growth. The surface area (mm2) of the frontal sinus was assessed by a Summagraphics decoder linked to a microcomputer. The results indicate that there is a significant correlation between maxillary length, mandibular length, symphysis width, condylar length, and frontal sinus size on a lateral cephalogram. The frontal sinus can possibly be used as an additional indicator when one is predicting mandibular growth.

Modelling net expenditure of hospitals in the Cape Province

Modelling the net expenditure of provincial hospitals in the Cape Province during 1989/90 on the number of inpatient days and outpatient visits (emergencies included) showed that on average the cost of a single outpatient visit is equivalent to 43% of the cost of an inpatient day in small hospitals. In specialist and academic hospitals this proportion increases to 70%. The current proportion of 33% used in the standardisation of hospitals is therefore inadequate. Multiple regression can be used to estimate the expected net expenditure for each hospital, which can then be used as a reference value. The need for separate accounting and reporting of the expenditure on outpatients is identified.

Risk factors for coronary heart disease in the black population of the Cape Peninsula. The BRISK study

A cross-sectional study of risk factors for ischaemic heart disease (IHD) in a random sample of 986 black people aged 15-64 years living in the Cape Peninsula revealed a population at lower risk for IHD than other South Africans. Blood pressures of 140/95 mmHg or above were found in 14.4% of males and 13.7% of females. Fifty-two per cent of males and 8.4% of females smoked, while 16.5% of males and 25.8% of females had a total cholesterol (TC) level imparting risk for developing IHD. In this population the TC level is not a good surrogate measure for low-density lipoprotein cholesterol because of the high level of high-density lipoprotein cholesterol (HDLC) found in this population. A protective HDLC/TC ratio of 20% was found in 96% of males and 96.1% of females. When considering the three major reversible IHD risk factors at a high level of risk, 30.8% of males and 12.5% of females had at least one such a risk factor. The population was frequently exposed to the media, with 80% listening to the radio every day and 55% watching television at least once a week. This suggests that a healthy lifestyle could be promoted successfully by means of these media. In addition, schools should promote a healthy lifestyle and the prevention of chronic degenerative diseases should be incorporated into the evolving primary health care services in South Africa.

Effect of lead and organophosphates on sperm morphology

Lead and organophosphates can exert a toxic action on the male reproductive function. A cross-sectional study involving 40 men was undertaken to investigate the effect of these toxins on sperm morphology. Based on the percentage of morphologically normal spermatozoa, subjects were divided into two groups. The control group (sperm morphology greater than or equal to 20% normal forms) consisted of 18 patients, and the study group (sperm morphology less than 5% normal forms) consisted of 22 patients. Lead, pseudocholinesterase, dibucaine, and fluoride levels were measured in blood samples of these men. The 22 men with low morphologically normal forms (less than 5%) did not display significantly different levels of the abovementioned substances compared to the control group.

Comparison between umbilical artery and vein endogenous digoxin-like immuno-active factor levels in normal and pre-eclamptic patients

Recent studies have pointed to the existence of an endogenous digoxin-like immuno-active factor (DLIF), which may be associated with hypertension and pre-eclampsia. The DLIF levels in the umbilical venous and umbilical arterial blood of neonates, as well as the maternal serum of primigravidas and multigravidas with and without pre-eclampsia, were determined by means of a commercially available radioimmunoassay kit, which is cross-reactive with DLIF, in 44 mothers and their babies in search for a possible placental, fetal or maternal origin of the DLIF. The mean placental and neonatal masses were significantly lower in the pre-eclampsia group than in the control group (P less than 0.01). However, the DLIF levels in the maternal serum, umbilical cord venous and umbilical cord arterial serum were statistically significantly higher in the pre-eclampsia group than in the control pregnant group (P less than 0.05). A very strong correlation was found between umbilical cord venous and arterial DLIF levels (r = 0.90; P = 0.001, Spearman rank-correlation coefficient). Although the mean DLIF level in cord arterial serum was lower than that of cord venous serum, statistical significance was not reached if the Bonferroni adjustment was applied to the P value.

[A study of the health services and needs of the elderly (SENSORG)]

Our department was approached by various welfare organisations who experienced problems with the placing of the frail elderly in suitable homes. The SENCARE project was planned to ascertain the health needs of the white and coloured elderly living in old-age homes and in the community and to identify the existing health services available to them by using the questionnaire method of measurement. The study was done in 3 phases: phase I in an urban area, phase II in a large rural town and phase III in 5 small rural towns. In the urban area too many healthy white elderly people live in old-age homes. The availability of services is poorer in the rural areas. In all 3 phases social and economic impairment is the major cause of dependence in both the white and coloured elderly population groups.

Noradrenergic function and hypothalamic-pituitary-adrenal axis activity in adolescents with major depressive disorder

Levels of plasma norepinephrine (NE), free 3-methoxy-4-hydroxyphenylglycol (MHPG), and cortisol in adolescents with major depressive disorder (10 girls, 1 boy; mean +/- SD age = 16.4 +/- 1.6 years, range = 14-19 years) did not differ significantly from those in a group of healthy adolescents (17 girls, 12 boys; mean +/- SD age = 15.9 +/- 1.5 years, range = 12-18 years). No correlations were observed between these variables and age within the adolescent groups. However, when the adolescent data were viewed in combination with data previously obtained for an adult population (De Villiers et al., 1987), significant positive correlations between the variables were observed within the patient group. A moderate positive correlation with age was also observed for patients' NE and free MHPG levels. No such correlations were observed for the combined control group. When groups were partitioned into three age categories, it became apparent that differences in the three variables between the patient and the control groups were restricted to elderly subjects (greater than 50 years). In adults (21-50 years old), only the patients' NE levels were significantly elevated. These findings suggest that duration of illness may be important in determining the full expression of the biochemical abnormality in major depression.

Hypoosmotic swelling test in the prediction of male fertility

The hypoosmotic swelling test (HOS) is a simple test to measure the functional competence of human sperm membranes. The question is, does a relationship exist between this competence and the fertilization potential of human spermatozoa? In this study the strongest correlation (r = 0.76) was obtained between sperm swelling and sperm viability (supravital staining). Only a moderate correlation (r = 0.50) was obtained with normal sperm morphology; weaker correlations were also obtained with the sperm penetration assay (r = 0.42) and human IVF (r = 0.24). The results, therefore, indicate that the HOS test has a limited predictive value. Notwithstanding this low concordance between sperm swelling and fertilizing potential, a less than 50% HOS test threshold was seen to be a definite indicator of a male factor.

Effect of rapid dilution of semen on sperm-bound autoantibodies

The effect of rapid dilution of autoantibody-positive semen on sperm-bound antibodies was studied in 12 male patients (0-100% IgA and 10-100% IgG). The direct immunobead test (IBT) and the sperm cervical mucus contact (SCMC) test were used to detect sperm-bound antibodies on spermatozoa before and after rapid dilution and swim up in HAM F-10 + 10% human blood serum. All patients tested had normal semen parameters. Sperm-bound antibodies detected after swim-up of semen samples ejaculated into 15 ml HAM F-10 + 10% serum (diluted) did not differ significantly from undiluted samples. Most values were lower (IBT and SCMC) but were not statistically significant. Sperm motility, forward progression, and morphology were statistically improved. Pregnancies resulting from washed semen (diluted) in combination with artificial insemination (AIH) or gamete intrafallopian tube transfer (GIFT) took place in spite of antibodies still present on the sperm membrane and can probably be attributed to improved semen quality, minimizing of ovum-sperm distance, and cervical mucus elimination.

Usefulness of sperm penetration assay in fertility predictions

The competence of the sperm penetration assay (SPA) to predict male fertility, as determined by normal sperm morphology and the fertilizing potential, as shown by human in vitro fertilization (IVF), was investigated. A significant correlation was obtained between normal sperm morphology and the SPA (phi = 0.623). A weaker correlation was however obtained with human IVF (phi = 0.397). Notwithstanding this weak association, a positive SPA (greater than 10%) was highly predictive (95%) of human IVF success. In contrast, a negative SPA (less than or equal to 10%) was associated with a high rate of false-negatives (65%). The SPA does however warn that a male factor may be present, as the mean fertilization rate of this group of patients was markedly reduced. The preincubation period for the spermatozoa did not play a major role in the predictive ability of a SPA outcome.

Antisperm antibody tests: traditional methods compared to ELISA

Enzyme-linked immunosorbent assays (ELISAs) to detect sperm antibodies can be a useful addition to other tests. ELISAs allow more quantitative and detailed information than some other tests, but results should be compared to those of other tests. This study was conducted to correlate results of an ELISA that used a sperm membrane extract as antigen with those of other tests. Semen, seminal plasma, and serum of 34 sperm-antibody-positive and 36 sperm-antibody-negative men were tested. There was poor correlation between the ELISA results and those of the other tests. Only the results of a direct immunobead test done on semen correlated fairly well with results from ELISAs done on serum. Further studies are needed on fertility-specific antigens that can be identified and isolated and then studied by means of ELISAs.

Does the wash-up and swim-up method of semen preparation play a role in sex selection?

Because of the higher built ratio of boys to girls (1.5 : 1) by in vitro fertilization (IVF) and gamete intrafallopian transfer (GIFT) at Tygerberg Hospital, the question arose as to whether the wash-up and swim-up method of semen preparation, used for our IVF procedure, plays a role in sex selection. Semen samples of 20 men were evaluated at different time intervals to determine the percentage of F-body-positive spermatozoa. It was found that the swim-up time affects the relationship between Y- and X-bearing spermatozoa, especially at time intervals of 30 and 45 min, where an optimum percentage of Y-bearing spermatozoa (p = 0.0039 and p = 0.0092, respectively) was found. Sperm obtained at these specific time intervals may influence the outcome of sex by IVF and GIFT in favor of males.

Low density lipoprotein kinetics in African Green monkeys showing variable cholesterolaemic responses to diets realistic for westernised people

African Green (vervet) monkeys were fed either an atherogenic Western diet (WD), a prudent diet (PD), or a high carbohydrate diet (HCD) for various lengths of time. Monkeys differed greatly in their response to the WD, and a strong negative correlation was observed between the fractional catabolic rates (FCR) of low density lipoprotein (LDL) and the total plasma cholesterol concentrations (r = -0.83 P = 0.0029). Similarly the individual synthetic rates (SR) of LDL plotted against the total plasma cholesterol concentrations showed a correlation coefficient of r = 0.94 P = 0.01 for WD animals. There was no correlation for PD or HCD animals for either SR or FCR and the total plasma cholesterol concentrations. The aortic lesion scores correlated with the SRs (r = 0.66 P = 0.040) but not with the FCRs. LDL turnover was also studied using 125I-labelled native LDL and methylated 131I-labelled LDL in African Green monkeys showing high or low cholesterolaemic response to an atherogenic Western diet. Measurements after 4 weeks and again after 6 months on the diet showed a decrease in both total and non-receptor mediated clearance of LDL. Receptor-mediated catabolism was significantly lowered in the hyperresponding group (P = 0.0011) and not in the hyporesponding group with a resultant significant difference between the two groups being P = 0.0355 after 6 months. Non-receptor mediated catabolism of LDL was similarly affected in that there was no significant difference between the two groups at 4 weeks but the clearance of methylated LDL was markedly lowered at 6 months, for the hyporesponding group P = 0.0003 and for the hyperresponding group P = 0.0184. Furthermore the hyperresponding group was depressed to a significantly greater extent when compared to the hyporesponding group (P = 0.0241).

Selection of medical students at a medical faculty in South Africa

The selection procedure at one medical faculty in the RSA was investigated. Students were admitted to the M.B. Ch.B. course on the basis of school results. Four groups were studied: matriculants; those selected after completing the 1st year of a B.Sc. course; those who had completed a full B.Sc. course; and those who had experience and other qualifications after leaving school. The matriculants were by far the largest group and the analysis of their marks received emphasis. Students who registered for their 1st year in 1980-1983 were followed up until the middle of their 3rd year. In total 635 students were assessed. The students' school results were compared with their preclinical marks. Chi-square tests for independence, multiple regression analysis, Pearson correlation coefficients and canonical correlation analysis were carried out. Although the results reflected a significant relationship between good selection marks and preclinical achievement, the strength of the association was too small for selection marks to have any reliable predictive value for an individual student. There was a low drop-out rate (5.4%) during the 1st year of study, but this rate increased threefold to 17.2% during the remaining preclinical period. This may indicate that the selection criteria were not specific enough to avoid this relatively large loss of students.

Injuries sustained in rugby by wearers and non-wearers of mouthguards

Previous studies have shown a higher prevalence of head and neck injuries in non-wearers when compared with wearers of mouthguards. The purpose of the present study was to compare the pattern of injuries to those of past studies and also to investigate whether the injuries sustained differed significantly between wearers and non-wearers. A sample of 321 university students participating on 555 player occasions was studied in a cross-sectional survey. No statistically significant differences (p greater than 0.05) were found between wearers and non-wearers of mouthguards with respect to head and neck injuries in general and to oral injuries in particular. We conclude that injuries sustained at rugby in this study were not associated with the use or non-use of mouthguards.

[Ovulation induction for in vitro fertilisation at the Tygerberg Hospital]

The protocol for in vitro fertilisation (IVF) at Tygerberg Hospital is presented and the results are analysed. Indications for ovulation induction for IVF included the following: (a) irreversible tubal damage; (b) infertility due to immunological factors; (c) male factor-infertility; and (d) endometriosis. A combination of human menopausal gonadotrophin (HMG) and clomiphene citrate (Clomid; Mer-National) and human chorionic gonadotrophin was used. Clomid is given in dosages of 100 mg for 5 days depending on the cycle length. Three doses of HMG (150 IU) are given on alternate days, starting on the second day of clomiphene treatment. If the leading follicle has not reached a mean diameter of 14 mm the day after the last HMG dose, another dose is given. This dosage is continued until the leading follicle reaches a diameter of 14 mm. A total of 109 cycles in 100 patients was analysed. Ova were considered to be mature as soon as the dominant follicle had reached a sonographic average diameter of 18 mm, another two follicles of 16 mm average diameter being present. Serum luteinising hormone levels were determined 4-hourly from the stage when the leading follicles exceeded an average diameter of 14 mm. In this study the pregnancy rate was 21,3% per laparoscopy and 24,4% per embryo transfer. The oestradiol levels on the 5th day of treatment have a predictive value of the length of stimulation.

The effect of serum supplementation on the cleavage of human embryos

The effect of serum supplementation was evaluated on 108 oocytes obtained from 29 patients. The oocytes were all mature and randomly distributed in two groups. Each ovum was paired with another ovum within the same patient. The experimental group contained no serum in the insemination and growth medium, but in the control group 10% serum was added to the insemination and growth medium. In the experimental group the cleavage rate was 66.7%, compared to 83.3% in the control group. The embryos from each patient were individually evaluated. The sign test was used for statistical analysis. A significant difference between the two groups (P = 0.01) indicated that in this study the addition of serum to the medium gives better cleavage results. The effect of serum on embryos is discussed, as well as the practical implications of this finding.

Sperm morphologic features as a prognostic factor in in vitro fertilization

To determine whether there is a prognostic value in the percentage normal sperm morphologic features in a human in vitro fertilization (IVF) program, the authors conducted a prospective study in women with bilateral tubal damage. Based on the percentage of morphologically normal spermatozoa, the patients were divided into four groups: group I, normal morphologic features between 0% and 14%; group II, 15% to 30%; group III, 31% to 45%; and group IV, 46% to 60%. One hundred ninety successful laparoscopic cycles were evaluated. In group I, 104 oocytes were obtained, of which 37% fertilized, but no pregnancy resulted; in group II, 81% of 324 oocytes were fertilized, with a pregnancy rate per embryo transfer (ET) of 22%; in group III, 82% of 309 oocytes were fertilized, with a 31% pregnancy rate; and in group IV, 91% of 69 oocytes were fertilized, with a pregnancy rate of 12%. Probability models indicated that there was a clear threshold in normal sperm morphologic features at 14%, with high fertilization and pregnancy rate in the groups with normal sperm morphologic features greater than 14%.

The development of one- and two-cell mouse embryos in the absence of human serum

One- and two-cell embryos were obtained from F1 hybrid female mice stimulated with human menopausal gonadotrophin and randomly distributed into two groups--group 1 (no serum) and group 2 (10% patient's serum). Fifty of 53 (94.3%) one-cell embryos in group 1 had cleaved to the blastocyst stage and 44 of 49 (89.79%) in group 2 after 96 hours (no significant difference--chi-square test). In the two-cell embryos in group 1, 78 of 89 (87.6%) reached the blastocyst stage after 72 hours and 80 of 86 (93.02%) in group 2 (no significant difference--chi-square test). According to microscopic evaluation cleavage to the blastocyst stage without serum supplementation is possible. The value of serum is discussed.

Follow-up study of physical growth of monozygous twins with discordant within-pair birth weights

In an attempt to determine the future growth of intrauterine growth-retarded babies, 14 pairs of monozygous twins, showing within-pair birth weight differences of 11% to 48% (median 28%), were followed prospectively for 3 to 9 years. Weight, length, and head circumference were measured biannually for the first 3 years of life and thereafter annually. At birth, the median within-pair percentage differences of weight (28%), length (6.2%), and head circumference (5.2%) were all significant (P less than .01). At 12, 24, and 30 months of age, these median within-pair percentage differences became insignificant for head circumference, length, and weight, respectively. The most rapid catch-up growth of the lighter twins occurred during the first 2 years of life. Analysis of individual pairs, however, showed suboptimal growth in both members of two pairs, although growth became concordant. In four other pairs, the lighter birth weight member remained growth retarded in comparison with the cotwin and showed within-pair differences in weight varying between 8% and 19%, in height between 1% and 6%, and in head circumference between 1.9% and 7%. All children with birth weights above the tenth percentile grew up normally, regardless of the extent of within-pair birth weight differences, with one exception. This exception was a pair in whom there were within-pair differences in child rearing. In the six pairs in which the smaller twin's birth weight was below the tenth percentile, only three pairs showed normal growth. In these six pairs a normal ponderal index in the lighter twin members was associated with poorer growth than a low ponderal index.(ABSTRACT TRUNCATED AT 250 WORDS)

Stromal and epithelial growth of the prostate during puberty

In 30 male Chacma baboons, prepubertal, pubertal, and adult animals have been identified by their testicular and prostatic weights. The volume of the stromal and epithelial components of caudal prostate were calculated from morphometric determination of the percentage volume of each component and the total caudal prostate volume. Both stromal and epithelial volumes increased at puberty and plateaued at maturity. These increases could be fitted to logistic curves that support the conclusion that stromal pubertal growth precedes epithelial pubertal growth. The stromal contribution to prostates of increasing size followed a model distinct to that of the epithelial contribution, thus suggesting that the factors (e.g., androgens) controlling stromal and epithelial growth are not identical. Stromal growth may be a prerequisite for pubertal epithelial development of the prostate.

Osmolarity studies with different containers and volumes in a human in vitro fertilization programme

In performing in vitro fertilization, a stable osmolarity in the medium surrounding the egg or embryo is of the utmost importance if a good fertilization and pregnancy rate is to be achieved. This study evaluated osmolarity changes in different volumes of fluid in the Falcon 3001 and 3037 Petri dishes and the Falcon 2058 tissue culture tube over a 24-hour period. It was found that the osmolarity was more stable in the Falcon 3037 Petri dish and in the tissue culture tube. The 3037 Petri dish was chosen for culturing human embryos.

Standards for the assessment of visual evoked potentials in an ethnically heterogeneous adult population

Visual evoked potentials (VEPs) were recorded by chequerboard pattern-reversal stimulation in 276 normal adult subjects aged 15-73 years. The sample comprised comparable white, coloured and black groups of both sexes. Significantly shorter latencies of the major positive component were found in both male and female black subjects compared with those in whites. No significant differences were found between the amplitudes in the different population groups, but females in each population group showed significantly higher amplitudes of the major positive component than males. There was a close relationship between latency and amplitude for both right and left eyes. Except in coloured females, a non-linear relationship of the major positive component with age was demonstrated, the shortest latency being at about 35 years of age. It is suggested that the following criteria be used in the evaluation of VEP recordings: latency as well as the difference between latencies and amplitudes of the two sides of the major positive component (P1) as compared with standardized values for ethnic, sex and age groups.