Power of mentorship for civilian and military acute care surgeons: identifying and leveraging opportunities for longitudinal professional development

Across disciplines, mentorship has been recognized as a key to success. Acute care surgeons, focused on the care of trauma surgery, emergency general surgery and surgical critical care, practice in a wide variety of settings and have unique mentorship needs across all phases of their career. Recognizing the need for robust mentorship and professional development, the American Association for the Surgery of Trauma (AAST) convened an expert panel entitled 'The Power of Mentorship' at the 81st annual meeting in September 2022 (Chicago, Illinois). This was a collaboration between the AAST Associate Member Council (consisting of surgical resident, fellow and junior faculty members), the AAST Military Liaison Committee, and the AAST Healthcare Economics Committee. Led by two moderators, the panel consisted of five real-life mentor-mentee pairs. They addressed the following realms of mentorship: clinical, research, executive leadership and career development, mentorship through professional societies, and mentorship for military-trained surgeons. Recommendations, as well as pearls and pitfalls, are summarized below.

CARD15/NOD2 risk alleles in the development of Crohn's disease in the Australian population

We have previously reported strong evidence for linkage between IBD1 and Crohn's disease (CD) in Australian Crohn's disease families. Three risk alleles for Crohn's disease, (Arg702Trp (C/T), Gly908Arg (G/C) and 980fs981 (-/C), were recently identified in the CARD15/NOD2 gene on chromosome 16, implicating this as the IBD1 locus. Using a novel diagnostic PCR-RFLP, we have examined the frequency of these alleles in 205 multiplex IBD families, 107 sporadic Crohn's disease cases and 409 normal individuals. We demonstrate that the three risk alleles are more frequent in Crohn's disease, than in controls, with allelic frequencies of 0.11, 0.02 and 0.07 respectively. Heterozygosity for individual variants conferred a three-fold increase in risk for Crohn's disease while substantially higher risks were associated with being homozygous or compound heterozygous. Despite a significantly lower population allele frequency for the frameshift mutation than reported by other groups, we see a similar contribution by this allele to the risk of developing Crohn's disease. While the three risk alleles influence susceptibility to Crohn's disease in Australia, we show that these alleles do not fully explain the linkage evidence and suggest that there are very likely additional IBD1 susceptibility alleles yet to be described in Australian CD at the NOD2 locus. We also show a second linkage peak in Australian CD that provides some support for a second disease susceptibility locus on chromosome 16.

Metabolic genotypes and risk for colorectal cancer

BACKGROUND

Inherited polymorphisms that influence carcinogen metabolism or the composition of bile may influence the risk for the development of colorectal cancer.

METHODS

The frequency of polymorphisms involving N-acetyltransferase 1 (NAT1), NAT2, cytochrome P450 1A1 (CYP1A1), CYP2D6, CYP2E1, glutathione S-transferase M1 (GSTM1), GSTT1 and apolipoprotein E were compared in 219 white adults with sporadic colorectal cancer and 200 white controls attending for blood donation at a blood bank. Polymorphisms were determined by using restriction fragment length polymorphism (RFLP) after amplification of genomic DNA by polymerase chain reaction (PCR). Data were analyzed by using standard statistical methods for a case- control study, and reported as odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

None of the genotypes, either alone or in combination, showed a strong association with colorectal cancer. Inheritance of the GSTT1 null genotype conferred a twofold risk of cancer that was statistically significant with crude data (OR 2.18; 95% CI 1.38-3.43), but not after adjustment for age (OR 1.91; 95% CI 0.99-3.70). There was also a trend towards a lower risk for proximal (right-sided) cancers in patients with apolipoprotein epsilon4 (OR 0.64; 95% CI 0.31-1.33).

CONCLUSION

No strong associations have been found between metabolic genotypes and colorectal cancer risk in Australia. Large studies will be required to confirm weak associations and to establish relationships between cancer risk, metabolic genotypes and exposure to dietary or other environmental carcinogens.

Meat, metabolic genotypes and risk for colorectal cancer

Persuasive data exist as to the importance of environmental factors in the pathogenesis of sporadic colorectal cancer. One possibility is that the effect of environmental factors varies between individuals, perhaps on the basis of inherited variation (polymorphism) in genes which influence the activation or inactivation of dietary carcinogens. Thus far, the focus has been on acetylator genes (NAT1, NAT2) and the activation of heterocyclic amines, carcinogens generated by cooking meat for prolonged periods at high temperature. Three case-control studies and one prospective study have shown a consistent trend towards higher risks for cancer with higher intakes of meat in rapid acetylators for NAT1, NAT2 or both genotypes. Other links between meat, cooking methods, metabolic genotypes and risk for cancer might include enhanced activation of polycyclic aromatic hydrocarbons and N-nitroso compounds by variant genotypes of CYP1A1 and CYP2E1, respectively, and modulation by meat of the protective effect of the E4 allele of apolipoprotein E on risk for cancer of the proximal colon.

Somatic mutations, acetylator status, and prognosis in colorectal cancer

BACKGROUND

Somatic mutations in K-ras and TP53 may be associated with both acetylator status and prognosis in colorectal cancer.

AIMS

To determine whether cancers with somatic mutations are more frequent in fast acetylators and whether mutations or acetylator status influence prognosis after colorectal surgery.

PATIENTS

One hundred consecutive subjects undergoing elective surgery for colorectal cancer.

METHODS

Acetylator status was determined by polymerase chain reaction (PCR) genotyping for polymorphism in the N-acetyltransferase 2 (NAT2) gene. Mutations in K-ras (codon 12) and TP53 were determined by PCR analysis using restriction enzyme digestion and single strand conformation polymorphism respectively. Survival from colorectal cancer for up to five years after diagnosis was analysed using the Kaplan-Meier product limit estimator. Cox proportional hazards regression was used to compare survival rates after adjusting for tumour stage.

RESULTS

Mutations in K-ras and TP53 were independent of acetylator status. By log rank test, survival was significantly reduced in subjects with TP53 mutations (p = 0.003) but was not significantly related to acetylator status or the presence of K-ras mutations. After adjustment for tumour stage, subjects with both TP53 and K-ras mutations had a 4.2-fold case fatality (95% confidence interval 1.5 to 11.6) when compared with that of a TP53 negative reference group.

CONCLUSION

The presence of both TP53 and K-ras mutations in colorectal tumours is an adverse prognostic marker which is independent of tumour stage.

Down-regulation of Fas gene expression in colon cancer is not a result of allelic loss or gene rearrangement

Expression of Fas, an apoptosis-inducing receptor, in colonic epithelium is progressively reduced during malignant transformation. We have examined the human Fas gene for loss of heterozygosity (LOH) and gross rearrangements in colon tumours and matched normal mucosa. Polymerase chain reaction (PCR) primers were designed to span a DraI restriction fragment length polymorphic site in the gene. Heterozygosity was detected in normal DNA samples by PCR amplification of the polymorphic site and restriction enzyme digestion. Thirty-eight of 88 patients (43%) with colon carcinomas were informative for the assay, and LOH was detected in 6 of the 38 (16%) corresponding tumours. Tumours from three patients with LOH did not express detectable Fas mRNA, and Fas expression was reduced or absent in 7 of 11 tumours from informative patients without LOH. Southern blotting of tumour DNA samples was used to detect rearrangement of the Fas gene, but no altered hybridization patterns were observed in 64 tumours analysed. These findings indicate that disruption of the Fas gene is not primarily responsible for the loss of Fas protein expression reported in colon cancer. We have also shown that loss of Fas gene transcription is common in these tumours, which may be due to epigenetic gene silencing.

The presence of a C1-inhibitor-like molecule (C1-INH-L) on human sperm: its involvement in sperm motility

PROBLEM

An 88-92-kDa C1-inhibitor-like molecule (C1-INH-L) was previously identified to elicit cytotoxic sperm antibody response in infertile men and women. Here, we document that it is present on the human sperm surface and could be detected by an enzyme-labeled immunoglobulin G (IgG) fraction of anti-human C1-INH antibody.

METHOD OF STUDY

Western blot analysis, enzyme-lined immunoadsorbent assay (ELISA) and computerized sperm motion analysis.

RESULTS

The existence of C1-INH-L on the sperm surface is calcium independent. Phosphatidylinositol-specific phospholipase C (PIPLC), EDTA, and acid (pH 3.0) could not remove the C1-INH-L from sperm, but trypsin did. Activated C1s was able to bind to the sperm surface. Immunofluorescence studies localized the protein to the head and midpiece of the sperm membrane. The C1-INH-L exists on both uncapacitated and capacitated sperm surfaces, which suggests that this protein is a sperm-surface protein. The heat-treated (56 degrees C, 30 min) IgG fraction of anti-C1-INH greatly reduced the percentage of motile spermatozoa and the progressive and path velocities in the absence of complement.

CONCLUSION

Our data suggest that C1-INH is a sperm membrane-anchored protein that may have complement and sperm motility regulatory function.

Evidence for the presence of the platelet-activating factor receptor in the CFW mouse preimplantation two-cell-stage embryo

Platelet-activating factor (1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine; PAF), a potent signaling phospholipid, has a significant role in preimplantation embryo development. CFW mouse embryos respond to PAF with improved development and implantation rates. PAF's signal transduction mechanism in other cell types is receptor mediated. However, embryonic mRNA for the PAF receptor has not been detected. The study objectives were to determine the presence of PAF receptor mRNA in CFW mouse two-cell embryos by reverse transcription (RT)-polymerase chain reaction and Northern blot analysis and to ascertain the effect of PAF on intracellular calcium levels (a receptor-mediated event). Total RNA was purified by acid-phenol extraction and ethanol precipitation. Complementary DNA was synthesized by RT. RNA was primed with oligo-dT plus PAF receptor-specific primer (3' to 5') at 42 degrees C for 60 min, 95 degrees C for 10 min, and 5 degrees C for 5 min. The RT product was amplified with Taq polymerase and PAF receptor-specific primer (5' to 3') at 94 degrees C for 5 min and 54 degrees C for 5 min for one cycle, and at 72 degrees C for 3 min, 93 degrees C for 90 sec, and 61 degrees C for 150 sec for 30 cycles followed by 72 degrees C for 10 min and then holding at 4 degrees C. The product was analyzed by agarose gel electrophoresis, producing a single band (610 base pairs [bp]), thus demonstrating the presence of PAF-receptor mRNA. Sequence analysis of the cloned 610-bp fragment confirmed that it is the PAF receptor. Northern blot analysis also confirmed the expression of the PAF receptor in the CFW mouse preimplantation two-cell-stage embryo. PAF treatment of the two-cell-stage CFW mouse embryo resulted in a fourfold increase in intracellular calcium over background levels.

Antibodies to endometrial transferrin and alpha 2-Heremans Schmidt (HS) glycoprotein in patients with endometriosis

PROBLEM

Identifying the endometrial antigens inciting autoimmunity is important in setting up an antibody assay for a non-invasive diagnosis and clinical monitoring of endometriosis.

METHODS

Two-dimensional gel electrophoresis of endometrial extracts, Western blot analysis, passive hemagglutination and enzyme-linked immunosorbent assay (ELISA), amino acid sequencing and molecular studies were done on chosen antigens. Forty-six women with endometriosis, 4 women with uterine leiomyomata, 4 with pelvic adhesions, 3 with repeat Cesarean sections (conditions that coexist with or predispose to endometriosis) and 46 controls participated.

RESULTS

Antigens with molecular weights (MW) of 64 kDa [isoelectric point (pI) of 3.5-4.0] and 72 kDa (pI of 4.5) bound to IgG in all patients with endometriosis, but not the controls. Amino acid sequencing of the proteins revealed that they had homology to alpha 2-Heremans Schmidt (HS) glycoprotein (MW: 64 kDa) and transferrin (MW: 72 kDa). Endometriosis patients had significant antibody levels to these two proteins (predictive value of 80-90%). The analysis of patients' endometrial RNA detected the message for alpha 2-HS glycoprotein and transferrin. Albumin (pI 5.5) and collagen (pI 3.5) failed to elicit antibody responses.

CONCLUSIONS

Patients with endometriosis have significant antibodies to endometrial transferrin and alpha 2-HS-glycoprotein. We can effectively use an antibody assay using these antigens for diagnosing endometriosis.

Effect of platelet-activating factor (PAF) on preimplantation mouse B6D2F1/J embryo formation

Platelet-activating factor (1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine; PAF) is a potent signaling phospholipid that has been implicated in a variety of reproductive processes. Human, rabbit, and mouse preimplantation embryos produce and secrete PAF. Anti-PAF antibodies interfere with mouse preimplantation development. A controversy exists on whether exogenous PAF is beneficial to preimplantation embryo development. The study objective was to determine the effect of exogenous PAF on embryo formation. One-cell mouse B6D2F1/J embryos were collected from PMSG/hCG primed females mated with fertile males. Embryos were exposed to PAF (0-10 microM) in MEM (0.3% BSA) for 15 min, then cultured in MEM (0.3% BSA) in a 5% CO2 in air, 95% relative humidity at 37 degrees C atmosphere, for 120 hr to the hatched blastocyst stage. PAF (0.1 or 0.01 microM) significantly (P < 0.05) improved preimplantation embryo development and formation in vitro. PAF at higher doses had no significant effect. Supplementation of culture medium with exogenous PAF was beneficial to preimplantation embryo development in B6D2F1/J mice.

Human follicular fluid and mouse cumulus cells act synergistically to enhance preimplantation mouse Balb/cJ embryo development

PROBLEM

The development of preimplantation mammalian embryos in vitro is less than optimal. Follicular fluid and cumulus cells have both been used, independently, to improve preimplantation embryo quality in culture.

METHOD

To determine the ability of mouse cumulus cell coculture in the presence of human follicular fluids to support preimplantation mouse Balb/cJ embryo development in vitro.

RESULTS

Culture of preimplantation mouse Balb/cJ embryo's independently in human follicular fluid or on mouse cumulus cells had no significant affect on blastocyst. The coculture of mouse Balb/cJ preimplantation-stage embryos on mouse cumulus cells in the presence of human follicular fluid significantly (P < 0.01) improved blastocyst development and the total number of cells per blastocyst.

CONCLUSION

Cumulus cells and follicular fluid have a positive synergistic affect on preimplantation mouse Balb/cJ embryo development and formation in vitro.

Target antigen(s) in endometrial autoimmunity of endometriosis

OBJECTIVE

To obtain the molecular weights (MW) of endometrial antigens eliciting immunoglobulin (Ig) G auto-antibodies in all endometriosis patients irrespective of their place of origin or race, and to verify their specificity and immunogenicity.

STUDY DESIGN AND RESULTS

We tested the serum and peritoneal fluid (P.F.) of 76 endometriosis patients and 24 controls from 4 cities against endometrial and implant antigens by Western blot analysis. Endometrial and implant antigens with MW of 34, 46/48, 64, 84, 94 and 120 kDa bound with IgG in serum and PF of most patients, but not the controls. Antigen(s) with MW of 64 kDa was reactive against serum or P.F. IgG of patients from all cities. Specificity: Endometrial and implant extracts did not react with monoclonal antibodies to WBC subsets and 5 sera with nuclear antibodies. Also, the presence of nuclear and endometrial antibodies did not correlate in 20 other patients with endometriosis. Immunogenicity: We immunized rabbits with the native and eluted (MW 29 to 68 kDa and > or = 68 kDa) endometrial and implant proteins. The antiserum had specific IgG binding to the same glandular epithelial antigens as those bound by the patient's serum.

CONCLUSIONS

Endometrial antigens with MW of 34, 46/48, 64, 94 and 120 kDa, especially 64 kDa appear to be specific, immunogenic and relevant to endometrial autoimmunity in all patients with endometriosis.

Anti-platelet activating factor (PAF) antibody inhibits CFW mouse preimplantation embryo development

OBJECTIVE

Our purpose was to investigate the effect of anti-PAF antibodies on CFW mouse embryo development in vitro.

DESIGN

We studied the in vitro development of CFW mouse one-cell-stage embryos cultured in MEM supplemented with anti-PAF, anti-IgG, or MEM alone to the hatched blastocyst stage.

RESULTS

Mouse embryos cultured with anti-PAF (1:5 dilution; 61%) significantly decreased embryo development compared to controls (MEM alone; 93%), whereas embryos cultured in anti-mouse IgG-supplemented MEM (1:10 dilution; 93%) had no effect.

CONCLUSIONS

The results provide additional evidence that PAF is produced and secreted by cleavage-stage embryos and is required during the preimplantation period.

Alpha-minimum essential medium (MEM) enhances in vitro hatched blastocyst development and cell number per embryo over Ham's F-10

PROBLEM

The development of mouse embryos in vitro is affected primarily by mouse strain-genotype and culture conditions. Embryo culture studies evaluate the effectiveness of culture conditions in supporting one- or two-cell mouse embryo development to the blastocyst stage by reporting the percentage blastocyst formation rate.

METHOD

Determining the cell number per cultured blastocyst may also help in determining embryo culture medium quality. The objective of this study was to determine the effect of MEM and Ham's F-10 on overall CFW mouse embryo development and hatched blastocyst cell number in vitro. CFW embryos cultured in MEM had significantly higher (87%; P < 0.001) hatched blastocyst rates than embryos cultured in F-10 (56%).

RESULTS

A significant difference in nuclei per hatched blastocyst was found between MEM and F-10 (P < 0.001). The results demonstrate that inbred mouse embryos have significantly higher blastocyst hatching rates and higher cell numbers per blastocyst when cultured in MEM.

Glutathione concentrations and glutathione S-transferase activity in human colonic neoplasms

Tissue concentrations of glutathione (GSH) and the activity of glutathione S-transferases (GST) are relevant to the inactivation of a variety of xenobiotics including carcinogens and anti-neoplastic drugs. In this study, GSH concentrations and GST activity were determined in 25 adenomatous polyps removed at colonoscopy, and in cancer and uninvolved 'normal' mucosa from 58 operative specimens containing colon cancer. We also examined the relationship between GSH concentrations, GST activity and rates of cell proliferation as assessed by flow cytometry. Concentrations of GSH were significantly higher in adenomas (P = 0.001) and cancer (P = 0.001) than in uninvolved mucosa while GST activity was significantly higher in cancer (P = 0.007). There was a positive relationship between GSH concentrations and GST activity in adenomas (P = 0.001) but not in uninvolved mucosa (P = 0.06) or cancer (P = 0.4). Concentrations of GSH and GST activity were independent of results from flow cytometry. The higher concentrations of GSH in colonic neoplasms and the raised activity of GST in cancer may contribute to their resistance to anti-neoplastic drugs.

Thyroid stimulating hormone causes cumulus expansion in mouse oocytes

The objective of this study was to determine if thyroid stimulating hormone (TSH) could induce cumulus expansion in mouse oocytes in-vitro. The effect of TSH was compared with the effects of LH and FSH. Oocytes were incubated in minimum essential medium (MEM) with and without hormones for 16 h at 37 degrees C under a humidified atmosphere of 5% CO(2) and 95% air. Then LH, FSH or TSH was added into the culture medium at a concentration of 0.25, 0.5, or 1.0 microg/ml, respectively. Cumulus expansion was scored in a subjective manner (O = no expansion; + = slight; ++ = moderate; +++ = maximum expansion) 16 h after addition of the hormones. The percentage of oocytes in the 4 categories of expansion was noted; LH failed (P>0.05) to induce cumulus expansion while TSH and FSH induced cumulus expansion (P<0.05) at all of the doses tested. For FSH, the 0.5 microg/ml dose showed the best response (26% = 0; 18% = +; 10% = ++; 46% = +++). For TSH, the 1.0 microg/ml dose showed the best response (38% = 0; 18% = +; 13% = ++; 31% = +++).

Effect of dehydroepiandrosterone on pentose phosphate pathway activity in the rat colon

1. The effects of fasting and fasting followed by refeeding on the activities of the oxidative pentose pathway (OPP) and the non-oxidative pentose pathway (NOPP) were estimated by the rate of production of 14CO2 from [1-14C] glucose in isolated rat colonocytes, and the production of hexose 6-phosphates from ribose 5-phosphate in rat colonic cytosols, respectively. 2. The OPP activity in colonocytes from rats in the fasted state was 50% lower when compared to colonocytes from rats refed after a fast. This indicated induction of the rate-limiting enzyme of the OPP, glucose 6-P dehydrogenase (G6-PDH) in the latter instance. No effect on the maximal catalytic activity of the enzymes of the NOPP was seen in colonocytes from rats refed after a fast compared with colonocytes from rats in the fasted state. 3. Isolated colonocytes obtained from the distal colon of rats refed after a fast, showed a significant decrease (30%) in OPP activity when incubated with 50 microM dehydroepiandrosterone (DHEA). A similar degree of inhibition was seen with 10 mM butyrate (P < 0.05). In contrast, using colonic cytosols, both DHEA and butyrate had no effect on the maximal catalytic activity of the NOPP. 4. Intraperitoneal injection (i.p.) of DHEA in rats refed after a fast showed a significant increase in the maximal catalytic activity of the NOPP in the distal colon (46%; P < 0.05). A similar elevation in the maximal catalytic activity of the NOPP was seen in the distal colon of DHEA treated pair-fed rats (43%; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Human follicular fluid contains a follicle-stimulating hormone (FSH) receptor binding inhibitor which has FSH agonist activity, is immunologically similar to FSH, but can be distinguished from FSH

We have previously reported the presence in human follicular fluid (hFF) of a high (greater than 5000) mol wt FSH receptor binding inhibitor (FSH-BI). This hFF FSH-BI was further purified by removal of material insoluble in acidified acetone (pH 4.1) but soluble in diethyl ether (pH 10.5), followed by molecular sieving through Sephacryl S-100. FSH-BI activity eluted from S-100 with an elution volume similar to that of hFSH, but could be distinguished from hFSH on the basis of a differential sensitivity to acid inactivation. Human FSH was inactivated in acetone at pH 4.1 (1 h, 25 C), whereas hFF FSH-BI retained activity under these conditions. Human FF FSH-BI also demonstrated FSH-like agonist activity, defined as the ability to stimulate basal levels of estradiol synthesis in cultured rat Sertoli cells. Human FSH-BI strongly cross-reacted to a commercially available monoclonal antibody used to measure serum hFSH. Indeed, recovery of FSH immunologic activity was significantly greater (134-fold on a mass basis) after partial purification, indicating that antibody recognition sites were apparently masked in unfractionated hFF. In summary, large mol wt hFSH-BI has been partially purified from hFF and found to be similar in size to pituitary hFSH and to have FSH-like agonist activity in vitro. Although distinguishable from pituitary hFSH on the basis of stability to acid, hFSH-BI appears immunologically related to pituitary hFSH so that measurements of hFSH levels in hFF using immunologic techniques should be interpreted with caution.

Low level of maternal serum alpha-fetoprotein: its associated anxiety and the effects of genetic counseling

A low maternal serum alpha-fetoprotein screening result can be expected to cause measurable anxiety for couples, particularly when the woman is younger than 35 years of age. This study was designed to investigate the levels of anxiety present in these patients and show the effectiveness of genetic counseling on this anxiety. The women and their partners were given the State Trait Anxiety Inventory before and after counseling. A control group of low-risk pregnant patients was also given the state anxiety inventory for comparison. The mean level of anxiety for the control group was 36, significantly lower than either the precounseling or postcounseling level of the group with low maternal serum alpha-fetoprotein screening results (p less than .05). The study shows that genetic counseling, in addition to appraising couples of the risks and options involved, does significantly reduce their anxiety level regardless of whether an amniocentesis was performed.

5-fluorouracil exposure during the period of conception: report on two cases

Two patients who were administered topical vaginal 5-fluorouracil for human papilloma virus lesions became pregnant during treatment. The outcomes in both cases were healthy with normal developmental landmarks at 6 months of age. This experience highlights the potential for a positive outcome.

Effect of removal of cumulus cells from one-cell mouse embryos on in vitro development

The effects of the removal of cumulus cells from fertilized mouse oocytes (one-cell embryos) and the presence of streptomycin in culture medium on in vitro development were studied. Ham's F-10 medium with (0.075 g/liter) or without streptomycin was supplemented with human serum (15%). Cumulus-intact embryos were harvested from oviducts after mice were superovulated with pregnant mare's serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG). Hyaluronidase (300 IU/ml) was used to remove the cumuli. Embryos were cultured (i) with cumulus/without streptomycin (n = 238), (ii) with cumulus/with streptomycin (n = 185), (iii) without cumulus/with streptomycin (n = 210), and (iv) without cumulus/without streptomycin (n = 218). Embryonic development was assessed 24, 96, and 120 hr after initiation of culture. Percentage two cells and percentage small or expanded blastocysts were not different (P greater than 0.05) among experimental groups. Percentages (mean +/- SE) hatched blastocysts for the four groups were (i) 36 +/- 8 and 54 +/- 7, (ii) 35 +/- 8 and 55 +/- 6, (iii) 19 +/- 5 and 42 +/- 6, (iv) 23 +/- 5 and 47 +/- 5 at 96 and 120 hr, respectively. Percentages all (small, expanded, and hatched combined) blastocysts were (i) 74 +/- 5 and 74 +/- 5, (ii) 74 +/- 9 and 72 +/- 5, (iii) 56 +/- 6 and 63 +/- 5, and (iv) 61 +/- 5 and 63 +/- 5 at 96 and 120 hr, respectively. A greater (P less than 0.05) percentage of embryos developed to blastocysts and hatched by 96 and 120 hr, when they were cultured with the cumulus intact.(ABSTRACT TRUNCATED AT 250 WORDS)

Statistical analysis of epidemiologic data of pregnancy outcomes

In this paper, a generalized logistic regression model for correlated observations is used to analyze epidemiologic data on the frequency of spontaneous abortion among a group of women office workers. The results are compared to those obtained from the use of the standard logistic regression model that assumes statistical independence among all the pregnancies contributed by one woman. In this example, the correlation among pregnancies from the same woman is fairly small and did not have a substantial impact on the magnitude of estimates of parameters of the model. This is due at least partly to the small average number of pregnancies contributed by each woman.

Discordance in deoxyribonucleic acid analysis of fetus and trophoblast

Molecular analysis of deoxyribonucleic acid extracted from trophoblast has become an important component of modern prenatal diagnosis. Discrepancies between trophoblast and fetal tissue in both chromosomal and metabolic analysis have been reported. We studied 50 paired fetal and trophoblast deoxyribonucleic acid specimens with a highly polymorphic probe for repetitive "minisatellite" regions of deoxyribonucleic acid that may be areas of high recombination. Four pairs showed persistent variations in bands consistent with differences in fetal and trophoblast deoxyribonucleic acid. Discordance in trophoblast deoxyribonucleic acid as a reflection of fetal genotype may be secondary to mitotic recombination or sister chromatid exchange in the trophoblast, and the possibility of discordance must be considered in interpreting the results of prenatal diagnostic testing on trophoblast specimens.

Activity of arylsulfatase A, B-glucosidase and hexosaminidases in chorionic villi at six, eight and ten weeks' gestational age

Chorionic villus sampling is becoming an accepted method of prenatally diagnosing metabolic diseases. There are few published data on sampling at various gestational ages. Different investigators, using different methods of chorionic biopsy, perform the sampling at various gestational ages. Accurate interpretation of results is dependent on reliable normal values, which could differ on the basis of gestational age. The enzymatic activities of arylsulfatase A, B-glucosidase and hexosaminidases were compared in trophoblast from six-, eight- and ten-week gestations. No significant differences in activity levels were detected. This finding confirms the accuracy of metabolic diagnosis for these enzyme-deficiency syndromes in trophoblastic tissue at gestational ages of six to ten weeks without a requirement for gestational-age-specific normal values.

Prevalence of radiologically defined osteoarthritis in the finger and wrist joints of adult residents of Tecumseh, Michigan, 1962-65

Radiographs of the fingers and wrists of adult participants in the Tecumseh Community Health Study in 1962-65 were examined for signs of osteoarthritis (OA). The severity of OA for each of 32 joints of the fingers and wrists was recorded for each individual. Attention was restricted to the 3035 participants who were 32 years of age or older and for whom a diagnosis of OA was available for each of 32 joints. Joint-specific prevalence rates of OA increased sharply with age for both sexes, and at the older ages, the prevalence rates for most joints were higher for females. Older individuals with OA also had a greater number of affected joints, with females having a greater number of affected joints than males. Of those individuals aged 44 years or younger, only 6.2% had one or more joints affected with OA. The percentages were 21.6 and 42.0% for those aged 45-59 years and 60 or more years, respectively. The distal interphalangeal (DIP) joints were the most frequently affected joints in all age categories for both sexes and OA in the proximal interphalangeal (PIP) joints was positively associated with OA in the DIP joints. However, controlling for the number of affected DIP joints, the PIP joints of older subjects were more likely to exhibit OA than the PIP joints of younger subjects. Though there is an association between OA in the DIP and PIP joints, there was only a small, nonsignificant association (OR = 1.24, 95% CI = 0.83, 1.84) between disease in the DIP and PIP joints of the same finger.

The value of oocyte reinsemination in human in vitro fertilization

The value of oocyte reinsemination in human in vitro fertilization (IVF) was evaluated in this study. Two groups of 25 cycles each were studied. In group 1 cycles, insemination of mature/questionably mature oocytes (judged by cumulus and corona cell appearance) at 6.5 hours postcollection yielded a fertilization rate of 42.3%. This value was significantly lower than that obtained with reinsemination (70.8%). In group 2, questionably mature oocytes were treated as immature and inseminated 24 to 30 hours postcollection. The fertilization rate of mature eggs in group 2 was 68.2%, with a reinsemination success rate of 40%. Triploidy rates and cleavage rates of mature eggs, fertilized either at initial insemination or reinsemination and of fertilized immature eggs, were similar within group 1 and group 2 cycles. In group 1, two pregnancies resulted from transfer of embryos arising solely from successful reinsemination, with one infant delivered. These results indicate that reinsemination offers a useful adjunct for IVF in cases where fertilization failure occurs.

Transurethral ultrasound-guided oocyte retrieval for in vitro fertilization

Thirty-nine follicular aspirations for in vitro fertilization were performed in 30 patients. Oocyte retrieval was performed by laparoscopy in 21 cases and ultrasound-guided transurethral aspiration in 18 cases. All procedures were performed by the same ovarian stimulation protocol and the same aspirating needle. In the laparoscopy group 150 oocytes were recovered from 177 follicles aspirated (85%). The fertilization rate was 69% (104/150) and cleavage rate, excluding triploidy, was 82% (85/104) for oocytes obtained by laparoscopy. Five clinical pregnancies occurred in the laparoscopy group for a pregnancy rate of 24% per cycle and 25% per transfer. In the transurethral ultrasound-guided group 77 oocytes were recovered from 103 follicles aspirated (75%). The fertilization rate was 79% (61/77) and cleavage rate, excluding triploidy, was 90% (55/61). Three pregnancies occurred for a pregnancy rate of 17% per cycle and 18% per transfer. None of these differences were statistically significant. Transurethral ultrasound-guided oocyte retrieval is a feasible alternative to laparoscopy for in vitro fertilization.

In vitro fertilization and birth after ultrasonically guided transurethral aspiration of oocytes

We have described an in vitro fertilization and embryo transfer accomplished by ultrasonically guided transurethral transvesical oocyte aspiration. Follicular aspiration using ultrasonography is a suitable alternative to traditional laparoscopic methods, and may have several advantages, including avoidance of surgical and general anesthesia complications. Further experience with this technique will clarify the benefits and/or risks, and this work is continuing.

Use of the logistic regression model for the analysis of proportionate mortality data

A new statistical analysis strategy for proportionate mortality data is proposed. It is assumed that the occupational exposure, if it has an effect on mortality, increases the rate of death for some subset of causes by a multiplicative factor while not affecting the rates for the remaining causes of death. The unconditional logistic regression model is shown to provide a structure for the data analysis, with one of the predictors being the logit of the probability in the reference population that death was due to the affected causes. Using this model, one can estimate the effect of exposure while simultaneously controlling for a number of potential confounding and selection variables. Also, this model avoids the problems of comparing standardized proportionate mortality ratios, which are indirectly standardized measures. The model is demonstrated on a set of proportionate mortality data for factory workers from the northeastern United States.

Passive smoking in childhood. Respiratory conditions and pulmonary function in Tecumseh, Michigan

The relationship of passive smoking to respiratory conditions and pulmonary function was assessed using a cross-sectional design in the defined population of Tecumseh, Michigan. The study population was made up of 3,482 children who were 0 to 19 yr of age at the 1962-1965 examination and for whom questionnaire information was available for both parents. Nearly 62% of children in this age group were exposed at the time of examination to at least 1 parent who smoked. Passive exposure to cigarette smoke was associated with an elevated prevalence of phlegm, wheeze, asthma, and chest colds among males and wheeze, bronchitis, and chest colds among females. Using logistic regression, offspring were shown to be 1.5 to 2.0 times more likely to have a respiratory condition if both their parents currently smoked than if both parents never smoked. FEV1, and FVC among males and Vmax50 among females were significantly lower by 5% in nonsmokers 10 to 19 yr of age whose parents were current smokers compared with similar offspring of never smoking parents. Respiratory conditions were generally more frequent and the level of lung function was generally lower for males from households where only mothers smoked compared with males from households where only fathers smoked, although sample size was limited. In females similar relationships were less consistent. Differences tended to be larger and more often significant for males than for females when respiratory symptoms and illnesses were examined.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of dental mottling in school-aged lifetime residents of 16 Texas communities

The severity of dental mottling in 2,592 school-aged, lifetime residents of 16 Texas communities was investigated in 1980-81 to identify factors associated with mottling and to construct a prediction model for the prevalence of mottling. The communities were selected to obtain a wide range of levels of fluoride in the drinking water. The children within each of the communities were contacted through their schools and received a dental examination to assess the severity of mottling. Information on demographic, dental health practice, and other candidate predictor variables was obtained from a questionnaire completed by a parent. A number of water quality measurements were also recorded for each community. White and Spanish-surname children had about the same prevalence of mottling while Blacks had a higher prevalence, odds ratio (OR) = 2.3, 95% confidence interval = 1.4, 3.7. Children from homes which had air conditioning had a lower prevalence of mottling (OR = .6, (0.4, 0.8)). The use of fluoride toothpaste or drops and the number of fluoride treatments were almost identical among those who did and did not develop moderate mottling. In addition to fluoride, total dissolved solids and zinc were water quality variables associated with mottling.

Mortality from coronary heart disease in the Tecumseh study. Long-term effect of diabetes mellitus, glucose tolerance and other risk factors

The coronary heart disease mortality of participants in the Tecumseh study was examined with particular emphasis on the roles of diabetes and glucose tolerance as risk factors. The cohort consisted of 921 men and 937 women aged 40 years and older who did not have evident coronary heart disease at entry to the study during the period 1959-1965 and whose outcome was determined in the period 1977-1979. Previously diagnosed diabetes was a statistically significant risk factor for coronary heart disease mortality in both sexes even after controlling for systolic blood pressure, serum cholesterol, relative weight, and cigarette smoking. High blood glucose score in nondiabetics was associated with excess coronary heart disease mortality after controlling for other risk factors, but the magnitude of this effect was substantially below that of diabetes. The predictive power of most risk factors except age itself decreased among progressively older segments of the population.

Diabetes mellitus in Tecumseh, Michigan. Prevalence, incidence, and associated conditions

A high proportion of the population of Tecumseh, Michigan, participated in comprehensive assessments of health, personal habits, and socioeconomic status during the periods 1959-1960 and 1962-1965. A total of 5735 persons older than 20 years of age, comprising 2749 men and 2986 women, form the subject of this report. Diabetics were identified at entry and contrasted to nondiabetics with respect to personal characteristics. During the period 1977-1979, health status of 69% of the eligible cohort was ascertained. Age, adiposity, and blood glucose level were the principal predictor of new cases of diabetes. Family history was a significant predictor only among middle-aged, overweight men. Diabetes tended to be related to central fat distribution as indicated by subscapular skinfold thickness. Predictors of new cases of diabetes were not necessarily related to prevalence of the disease in this population.

HLA-A2 and type 2 (insulin independent) diabetes mellitus in Pima Indians: an association of allele frequency with age

In Pima Indians with Type 2 (insulin independent) diabetes mellitus, HLA-A2 allele frequencies were inversely associated with age, (0.72, 0.59, and 0.52 in those less than 35, 35 to 54, and 55 years old and over, respectively). This suggests that there may be a gene closely linked with the HLA-A locus which plays a role in the expression of diabetes in the Pimas by contributing to an earlier age of onset. HLA-A2 was found in 65% non-diabetic and 81% of 191 diabetic subjects (relative risk = 2.2).