Foot rot of pigs: the influence of biotin supplementation on foot lesions in sows

A herd of 116 sows with a high frequency of foot lesions and lameness was divided into two groups, A and B. Group B was supplemented with 1160 microgram per day of biotin in pregnancy and 2320 microgram per day in lactation, over a 12-month period. No improvement occurred in the condition of the feet or skin. Gilts introduced as replacements to the herd were allocated alternately to the groups. Those receiving biotin (group B) showed significantly fewer lesions of heel erosion, white-line, heel bruising and "corn", and the severity and number of lesions of the lateral hind claws were also significantly improved.

Loss of Hfr DNA from Escherichia coli merozygotes during inhibition of conjugation by nalidixic acid

The effect of nalidixic acid on conjugal recombination was studied in matings with recipient strains carryingrecA200, a mutation which confers a thermosensitive Rec−phenotype. Addition of nalidixic acid to Hfr Nals× F−NalRrecA200matings at low temperature (35 °C) caused a sharp 10- to 20-fold decline in the yield of recombinants if plating on selective agar was delayed. Two separate processes were identified as being responsible for this decline. Those merozygotes in which the transferred DNA was free of the donor cell lost the ability to form recombinants through inactivation of this DNA, an effect which could be prevented by using exonuclease deficient (recB sbcB) recipients or by prior growth of exonuclease proficient recipients in medium containing 0·25 M sodium chloride. No more than 50% of the observed loss of recombinants could be attributed to this effect. The remaining merozygotes lost their ability for recombinant formation provided mating pairs, and presumably the displaced donor DNA strand, remained intact. This process was thought to involve withdrawal of transferred DNA (DeHaan & Gross, 1962) and was studied in isolation in matings withrecA+, orrecA200 recB sbcBrecipients. A mechanism involving re-annealing of the displaced Hfr DNA to the donor molecule as a result of nalidixic inhibition of gyrase activity in the donor causing relaxation of DNA supercoils is proposed to account for this withdrawal event.

Cell surface A, B, or O(H) blood group antigens as an indicator of malignant potential in stage A bladder carcinoma

The major blood group antigens A, B or O(H) are present on normal bladder epithelium. The presence or absence of these antigens on the cell surface of bladder tumors has been determined in a retrospective longitudinal study using biopsy material from 322 patients who fit the following criteria: 1) the patient presented initially with a superficial bladder tumor, 2) the patient had followup examination for at least 5 years or until evidence of tumor invasion of bladder muscle and 3) the paraffin-embedded tumor specimens were still available. Of 80 patients with stage A tumors that subsequently became invasive 71 (88 per cent) showed deletion of A, B or H antigens from the original superficial tumor. On the other hand, of 146 patients who had no recurrence of superficial tumor for at least 5 years 127 (87 per cent) retained A, B or H antigens. Of 96 patients who had 1 or more superficial recurrences 87 (90 per cent) retained antigens on the initial and subsequent tumors. Analysis of transitional cell surface antigens should help in the identification of those patients with superficial disease who are at greatest risk for invasive bladder cancer.

Primary amyloidosis of renal pelvis and renal cortical adenoma

A case of primary renal pelvic amyloidosis presenting with spontaneous extravasation is discussed. The association with an ipsilateral renal cortical adenoma is noted. A review of the pertinent literature is given.

Stimulation of hormone-responsive adenylate cyclase activity by a factor present in the cell cytosol

1. Homogenates of whole tissues were shown to contain both intracellular and extracellular factors that affected particulate adenylate cyclase activity in vitro. Factors present in the extracellular fluids produced an inhibition of basal, hormone- and fluoride-stimulated enzyme activity but factors present in the cell cytosol increased hormone-stimulated activity with relatively little effect on basal or fluoride-stimulated enzyme activity. 2. The existence of this cytosol factor or factors was investigated using freshly isolated human platelets, freshly isolated rat hepatocytes, and cultured cells derived from rat osteogenic sarcoma, rat calvaria, mouse melanoma, pig aortic endothelium, human articular cartilage chondrocytes and human bronchial carcinoma (BEN) cells. 3. The stimulation of the hormone response by the cytosol factor ranged from 60 to 890% depending on the tissue of origin of the adenylate cyclase. 4. In each case the behaviour of the factor was similar to the action of GTP on that particular adenylate cyclase preparation. 5. No evidence of tissue or species specificity was found, as cytosols stimulated adenylate cyclase from their own and unrelated tissues to the same degree. 6. In the human platelet, the inclusion of the cytosol in the assay of adenylate cyclase increased the rate of enzyme activity in response to stimulation by prostaglandin E1 without affecting the amount of prostaglandin E1 required for half-maximal stimulation or the characteristics of enzyme activation by prostaglandin E.

The effects of race and social class on clinical judgment

Asked 61 male clinical psychologists (21 blacks and 40 whites) to assess case histories that were presented to them to determine whether racial or social class biases could be detected. In order to avoid the apparent artificial results or weak interpretations of past research, only cases with concurrently validated diagnoses and 4-year follow-up were used. An equal number of positive and negative clinical outcomes were included. Diagnosis, disposition, and rated severity were studied. The following results were found: (1) diagnosis for all psychologists was guided by case characteristics, not bias; (2) severity was related strongly to diagnosis; (3) disposition followed judgments of severity and diagnosis, not bias. The question was raised whether clinical investigators may not have overdramatized bias in psychodiagnosis and clinical judgment.

Linkage analysis between the major histocompatibility system and insulin-dependent diabetes in families with patients in two consecutive generations

We have histocompatibility (HLA) genotyped 28 families with insulin-dependent diabetics in two or more consecutive generations, usually parent and child. This strategy of ascertainment was used to maximize the likelihood of obtaining a homogeneous type of disease within a family, and an autosomal dominant mode of inheritance. 76 diabetics and 169 nondiabetics were studied in these families. The frequencies of the antigens Dw3 and Dw4, and the genotype Dw3/Dw4 among the diabetics are 59, 68, and 30%, respectively, as compared with 15, 12, and 2% in normal controls, and 43, 41, and 10% in the nondiabetic relatives of the diabetics. Dw2 is present in only one diabetic (4%), as compared with 18% in normal controls and 17% in nondiabetic relatives.HLA haplotype concordance was analyzed for sib pairs in relation to the haplotype shared by the affected parent/child pair, and for the diabetic sib pairs within each sibship. The results failed to reveal deviations in the expected HLA haplotype assortment. Assuming an autosomal dominant mode and several penetrance levels, linkage analysis between the HLA and diabetes was performed. The total lod score is 0.37 for a recombination fraction of 0.29 at 50% penetrance. Although the linkage and concordance analysis results are inconclusive, they seem to be different from those reported by us for families with normal parents and two or more diabetic sibs. Because ascertainment biases may have influenced these results in an unquantifiable manner, it is not certain whether the two types of families are genetically different. However, the marked difference in the lod scores for the 50% penetrant autosomal recessive model between the two types of families is compatible with a genetic dissimilarity between them. The high frequency of the Dw3 and Dw4 antigens, the Dw3/Dw4 genotype, and the decreased frequency of Dw2, however, indicate the existence of two or more important diabetic genetic factors associated with the D region of the HLA in these families.

A microcomputer-based research system for the optical analysis of agar-cultured micro-organism colonies

A system which has been developed for the automatic of agar-cultured microorganism colonies is described. A camera of the line-scanning type is used to scan the plates and details of the hardware and software development are explained. Flow diagrams are included which illustrate the operation of the system, but, as yet, no results are available. The prototype machine is undergoing evaluation testing.

Distribution and biosocial correlations of blood pressure levels in Johannesburg blacks

Blood pressures were measured in a sample of Johannesburg Blacks consisting of 5 018 men and 5 028 women attending the local Labour Bureau. Blood pressure levels correlated positively with age and body mass and were higher in males than females when weight was taken into account. Hypertension was common in both sexes and at most ages; in the 4th decade about one-third of men and women had phase 4 diastolic pressures greater than 90 mmHg. Correlations of blood pressure with a number of social variables were generally unimpressive. There was some evidence that blood pressure was inversely related to educational status and was higher in young adults who (a) lived apart from their families compared with those who lived in family units, and (b) grew up in a rural area and then migrated to Johannesburg compared with those who had lived in Johannesburg all their lives.

The effect of isomeric trans-18:1 acids on the desaturation of palmitic, linoleic and eicosa-8,11,14-trienoic acids by rat liver microsomes

The inhibitory effects of the positional isomers of trans-18:1 acids on the desaturation of palmitic acid to palmitoleic (delta 9-desaturase), linoleic to gamma-linolenic (delta 6-desaturase) and eicosa-8,11,14-trienoic to arachidonic acid (delta 5-desaturase) were investigated. These trans-18:1 acids were found to be inhibitory for the microsomal delta 6-, delta 9- and delta 5-desaturases of rat liver. The position of the double bond in the trans-18:1 acids seems to be important in determining the degree of inhibition. At inhibitor/substrate ratio of 3:1, the delta 6-desaturase was most strongly inhibited by trans-delta 3, -delta 4, -delta 7 and -delta 15-18:1 isomers, whereas the delta 9-desaturase was most strongly inhibited by trans-delta3, -delta 5, -delta 7, -delta 10, -delta 12, -delta 13 and -delta 16 isomers. At inhibitor/substrate ratio of 6:1, the delta 5-desaturase was most strongly inhibited by delta 3-, delta 9-, delta 13- and delta 15-isomers. When 18:0 was added to the incubations of 16:0, 18:2 and 20:3 at the same I/S ratios used for the trans-18:1 acids, weak inhibition for delta 9- desaturase and no inhibition for delta 5- and delta 6-desaturases was observed.

Feasibility of blood glucose self-monitoring in unstable insulin-dependent diabetes

We have studied the impact of home blood glucose measurements with the Ames Dextrostix/Eyetone system on the metabolic control of 17 insulin-dependent, ketosis-prone, unstable diabetic patients. Thirteen patients (69 patient-months) were enrolled in a comprehensive program designed to achieve excellent metabolic control and which included the daily use of the Eyetone meter. Eleven of these patients were diabetic kidney recipients on daily prednisone. The improvement of the metabolic control, as assessed by daily home blood glucose measurements, was highly significant (P < 0.001) in 11 patients (85%). The control was still inadequate, however, in at least seven patients. In four unstable diabetic patients who were given the meter for 4 mo but were not followed closely during this period, modest or no improvement in metabolic control was observed. The Eyetone meter proved highly precise and accurate in our patients' hands. Several patients achieved a coefficient of variation of less than 5 (in 10 consecutive determinations) and a correlation coefficient with the Beckman glucose analyzer of 0.96. We concluded that the metabolic control can be markedly improved in the most unstable diabetic patients with home blood glucose measurements, provided the patients receive adequate and frequent encouragement and diabetic teaching. Without the latter, at least in unstable diabetes, whether patients are compliant or not, the instrument may have little impact on control.

A circulating humoral pressor agent in Dahl S rats with salt hypertension

1. In Dahl S rats becoming hypertensive while on a diet of high NaCl content there appears to be a blood-borne humoral agent which produces vasoconstriction in a bioassay using the isolated hindquarters of rats. 2. This vasoconstrictor effect strongly suggests the presence of a humoral pressor agent or the lack of a vasodilator agent in the blood of hypertensive S rats. 3. The vasoconstrictor effect is not due to high renin concentrations. 4. This humoral vasoconstrictor action could partly account for the high vascular resistance in the hypertensive S rat.

Positive results from outpatient mental health intervention

Collected data on 3,342 outpatients over 2 years. A 4-year follow-up of successful outcomes was conducted on each of the cases. Hospitalized patients showed a 30% success rate. The success rate for the group that was recommended for no treatment was 60%. The success rate for patients who completed outpatient treatment increased to 78%. A patient's expectation of outcome, the clinician's assessment of reason for referral, the diagnosis, and age were the most powerful predictors of success. These findings demonstrate the following: (a) procedures for assessment and intervention can be successful; and (b) a significant portion of the population can be served by intervention with proper selection.

Effect of practice and training in spatial skills on embedded figures scores of males and females

The effect of practice and training in spatial skills on scores obtained by male and female students on the Embedded Figures Test was examined. Forms A and B were administered 6 wk. apart to three groups of subjects (ns = 28, 27, 27) enrolled in drafting, mathematics, and liberal arts courses. During the pretest-posttest period the drafting students received training while the other two groups served as controls. Analysis indicated (1) no initial sex difference in test scores; (2) liberal arts students differed significantly from drafting and mathematics students, but there was no significant difference between the last two groups; (3) all groups improved with practice; (4) women receiving training improved more than women who did not; (5) there was a trend toward women receiving spatial training scoring more poorly than males receiving training on the pretest, but there was no significant difference on the posttest. These results suggest that sex differences in embedded-figures scores found by many previous experimenters may have been associated with differences in prior experience in spatial skills and by a confounding of sex with area of academic study.