Effect of stapled versus layered skin closure on surgical site occurrences after abdominal wall reconstruction.

BACKGROUND: The effect of skin closure technique on surgical site occurrences (SSO) after open abdominal wall reconstruction (AWR) with retromuscular polypropylene mesh placement is largely unknown. We hypothesize that layered subcuticular skin closure with cyanoacrylate skin adhesive is protective of surgical site infection compared to standard stapled closure. METHODS: A retrospective review utilizing the Abdominal Core Health Quality Collaborative (ACHQC) database of all patients at Prisma Health-Upstate. All patients with open abdominal wall reconstruction (AWR) of midline incisional hernia defects with retromuscular polypropylene mesh placement from January 2013 to February 2020 were included. Patient demographics, comorbidities, type of hernia repair with mesh location, method of skin closure, and SSOs were collected. Skin closure method was divided into two groups, reflecting a temporal change in practice: staples (historical control group) versus subcuticular suture with cyanoacrylate skin adhesive with/without polymer mesh tape (study group). Primary endpoint was SSI and SSO. Secondary endpoints were SSO or SSI requiring procedural intervention (SSOPI/SSIPI). Standard statistical methods were utilized. RESULTS: A total of 834 patients were analyzed, with 263 treated with stapled skin closure and 571 with subcuticular and adhesive closure. On univariate analysis, the incidence of SSI was significantly lower in the study group (11.8 vs 6.8%; p = 0.002), as was the need for SSIPI (11.8 vs 6.7%; p = 0.015). Rate of SSO was not significantly different between groups (28.1 vs 27.2%), but the rate of SSO requiring intervention was lower in the study group (14.1 vs 9.3%; p = 0.045). CONCLUSION: Layered skin closure technique, including subcuticular closure and adhesive, may reduce the risk of surgical site infection after open AWR. A prospective randomized trial is planned to confirm these findings.

Relative resistance index (RRI) - a scoring system for antibiotic resistance in Pseudomonas aeruginosa.

BACKGROUND: There is a need to measure antibiotic resistance of Pseudomonas aeruginosa (PA) in cystic fibrosis (CF), either qualitatively or quantitatively, to inform patient management. The aim of this study was to develop a simple method by which resistance can be quantified by calculating a relative resistance index (RRI), and to assess correlation of RRIs with clinical variables. METHODS: In our model, RRIs were calculated based on resistance to aztreonam, ceftazidime, ciprofloxacin, colistin, meropenem, tazocin, temicillin and tobramycin. Eighty-five adults with CF and chronic PA colonisation were identified. For each, all PA cultures were allocated a score of 0 for susceptible, 0.5 for intermediate resistance or 1 for resistance for each antibiotic listed above, and the RRI calculated by dividing the sum of these by the number of antibiotics, giving a maximum score of 1. The mean RRIs for all cultures were correlated with key clinical variables monitored in CF patients (including age, FEV1, IV antibiotic days and BMI). RESULTS: RRIs for non-mucoid PA exhibited moderate positive correlation with total number of IV days (r = 0.405; p < 0.001) and moderate negative correlation with FEV1 % predicted (r = -0.437; p < 0.001). RRIs were not significantly correlated with duration of colonisation, typing (clonal vs other strain) or BMI. Median RRIs were significantly higher for females (0.26, IQR 0.13-0.54) than males (0.18, IQR 0.07-0.37) for non-mucoid PA only (p = 0.03). CONCLUSIONS: RRI is an easily calculated measure that correlates with other clinical variables in CF patients and enables quantitative monitoring of resistance.

Performance evaluation of a pilot-scale anaerobic membrane bioreactor (AnMBR) treating ethanol thin stillage.

The ethanol industry has grown rapidly during the past ten years, mainly due to increasing oil prices. However, efficient and cost-effective solutions for treating thin stillage wastewater have still to be developed. The anaerobic membrane bioreactor (AnMBR) technology combines classical anaerobic treatment in a completely-stirred tank reactor (CSTR) with membrane separation. The combination of these two technologies can achieve a superior effluent quality and also increase biogas production compared to conventional anaerobic solutions. A pilot-scale AnMBR treating thin stillage achieved very high treatment efficiencies in terms of chemical oxygen demand (COD) and total suspended solids (TSS) removal (>98%). An average permeate flux of 4.3 L/m2 x h was achieved at relatively low transmembrane pressure (TMP) values (0.1-0.2 bars) with flat-sheet membranes. Experience gained during the pilot-scale studies provides valuable information for scaling up of AnMBRs treating complex and high-strength wastewaters.

Computed tomography imaging in ventral hernia repair: can we predict the need for myofascial release?

INTRODUCTION: Currently, the need for additional myofascial release (AMR) in addition to retromuscular dissection during open Rives-Stoppa hernia repair is determined intraoperatively based on the discretion of the surgeon. We developed a novel method to objectively predict the need for AMR preoperatively using computed tomography (CT)-measured rectus width to hernia width ratio (RDR). METHODS: A retrospective chart review of all patients who underwent open retro-muscular mesh repair of midline ventral hernia between August 1, 2007 and February 1, 2018, who had a preoperative CT scan within 1 year prior to their operation. The primary endpoint was the ability of the defect ratio to predict the need for AMR in pursuit of fascial closure. The secondary endpoint was the ability of Component Separation Index (CSI) to predict the need for AMR to obtain fascial closure. RESULTS: Of 342 patients, 208 repaired with rectus abdominis release alone (RM group), while 134 required AMR (RM + group). An RDR of > 1.34 on area under the curve analysis predicted the need for AMR with 77.6% accuracy. There was a linear decrease in the need for AMR with increasing RDR: RDR < 1 required AMR in 78.8% of cases, RDR 1.1-1.49 in 52%, RDR 1.5-1.99 in 32.1%, and RDR > 2 in just 10.8%. Similarly, CSI > 0.146 predicted the need for AMR with 76.3% accuracy on area under the curve analysis. CONCLUSION: The RDR is a practical and reliable tool to predict the ability to close the defect during open Rives-Stoppa ventral hernia repair without AMR. An RDR of > 2 portends fascial closure with rectus abdominis myofascial release alone in 90% of cases.

Prophylactic mesh augmentation using permanent synthetic mesh: outcomes of keyhole and Stapled Ostomy Reinforcement with Retromuscular Mesh techniques.

INTRODUCTION: Parastomal hernias (PSH) are the most common complication of stoma creation and can cause significant morbidity. We present a consecutive series of patients receiving prophylactic mesh augmentation (PMA) for prevention of PSH. METHODS: This retrospective review evaluates the efficacy and outcomes of PMA for PSH prevention, and retrospectively compares traditional keyhole PMA (tPMA) (n = 28) with a prophylactic Stapled Ostomy Reinforcement with Retromuscular Mesh technique (pSTORRM) (n = 24). RESULTS: PMA was performed in 52 cases between January 2015 and July 2018. All cases used a large-pore, non-coated, mid-weight polypropylene mesh placed in the retrorectus space. With a median follow-up of 16 mos, parastomal hernia was confirmed in 11.5% (n = 6), 5 of whom were symptomatic. patient-reported outcomes (PRO) indicated 6 additional patients with symptoms associated with PSH without clinical or radiographic confirmation. Patients had similar comorbidities and operative characteristics between tPMA and pSTORRM techniques, and no difference in a median follow-up. pSTORRM patients had fewer surgical site infections (8.3 vs 32.1%; p = 0.046) and occurrences (12.5 vs 46.4%; p = 0.015), and lower rate of PSH, though not statistically significant (4.2 vs 17.9%; p = 0.195). CONCLUSION: Permanent synthetic mesh placed as a sublay in the retromuscular space is safe and appears to decrease the risk of PSH formation after the creation of permanent stomas. A stapled technique may provide advantages over a traditional keyhole technique.

Does reduced-intensity allogeneic transplantation confer a survival advantage to patients with poor prognosis chronic lymphocytic leukaemia? A case-control retrospective analysis.

BACKGROUND: Reduced-intensity conditioning (RIC) allogeneic haemopoietic cell transplantation (allo-HCT) is increasingly considered as a therapeutic option for younger patients with poor-risk chronic lymphocytic leukaemia (CLL). In this retrospective analysis, we assessed the outcomes of CLL patients undergoing RIC allo-HCT compared with a group of matched controls that were candidates for transplantation but did not have a suitable donor or refused the procedure. PATIENTS AND METHODS: Cases comprised 37 patients who underwent RIC allo-HCT. Haemopoietic cell grafts were harvested from HLA-matched siblings (27) and unrelated donors (7). Controls consisted of 43 patients from the same institutions who received conventional therapy only. Matching variables were age at diagnosis and time to first CLL-specific therapy. RESULTS: Both patient groups were well balanced in terms of cytogenetics by FISH, CD38 and ZAP-70 expression, and immunoglobulin heavy-chain variable region mutational status. Median overall survival was 113 months for HCT patients and 85 months for controls when calculated from time of diagnosis (P = 0.072) and 103 and 67 months, respectively, when calculated from time of first therapy (P = 0.041). CONCLUSION: RIC allo-HCT is a reasonable option for patients with high-risk CLL. However, these results require confirmation before the procedure can be recommended outside clinical trials.

Sediment distribution on the mid-ocean ridges with respect to spreading of the sea floor.

An abrupt change in sediment thickness between the crests and flanks of the mid-ocean ridges can be interpreted as a major discontinuity in the rates either of spreading of the sea floor or of accumulation of sediment. The preferable interpretation of the data is that the process of spreadig of the sea floor is intermittent and that the present cycle of spreading commenced around 10 million years ago. following a long period Of quiescence during which most of the observed sediments were deposited.

Age of the bay of biscay: evidence from seismic profiles and bottom samples.

Paleomagnetic data and marine magnetic surveys suggest that the Bay of Biscay was created by rifting due to an anticlockwise rotation of the Iberian peninsula. The period during which movement occurred is not known precisely, but a rotation, amounting to 22 degrees, appears to have taken place in post-Eocene time. To provide independent evidence on the age of the rift, bottom samples from the Biscay abyssal plain have been related to the distribution of seismic reflectors within the sediments. The investigation shows that a large part of the Bay of Biscay was in existence in late Cretaceous times and that the data can be interpreted in terms of some early Tertiary rotation. However, the amount of possible Tertiary opening is appreciably less than the paleomagnetic results suggest. In view of the fact that reflectors of Middle-Upper Miocene age can be traced as undisturbed horizons across the bay, all tectonic movements must have ceased by the early Miocene.

Tertiary sediment from the East pacific rise.

More than 50 cores ranging in age from Pliocene to Lower Miocene have been recovered from the East Pacific Rise. Near the crestal regions the sediment cover is thin or lacking, and only Pleistocene sediments were recovered. On the flanks, the sediment thickness increases and pre-Pleistocene sediments are encountered. This pattern of increasing age and increasing sediment thickness away from the axis of the rise is in agreement with that predicted for spreading of the ocean floor.

Lower cretaceous sediments from the northwest pacific.

The first occurrence of deep-sea Lower Cretaceous (Albian) sediments in the Pacific Ocean is reported from the Shatsky Rise at 31 degrees 51'N, 157 degrees 20'E. Seismic-profile records indicate that the core was taken between the extensive seismic reflectors A and B. Two hundred meters of unconsolidated sediment lies between the core site and basement (B) and suiggests that the sediment just above basement may be at least as old as Middle Jurassic.

Investigation of horizon Beta.

Horizon beta is a subbottom reflector in the North Atlantic deep ocean sediments that extends over a large portion of the North America basin. Cores from an outcrop of beta contained shallow-water Aptian-Albian sediments and deep-water Cenomanian sediments. A core near an outcrop of a deeper horizon, horizon B, contained shallow-water Lower Cretaceous (Barremian-Hauterivian) sediments. These cores can be interpreted to support extensive subsidence of the eastern portion of the basin in early Cretaceous time. It is equally likely that the shallow-water deposits are a result of sediments slumping into an already deep basin. A reconciliation of these interpretations depends upon the JOIDES project.

Design and benchtop validation of a handheld integrated dynamic breast imaging system for noninvasive characterization of suspicious breast lesions.

We have developed a portable, handheld, integrated, dynamic breast imaging system that integrates a near infrared tissue oximeter, clinical ultrasound, and two pressure sensors for noninvasive detection of pressure-induced structural and functional dynamics of suspicious breast lesions. A series of benchtop tests were conducted to validate multiple performance characteristics of the integrated dynamic near infrared/ultrasound breast imaging system (idNIRUS), including the reconstruction of the absorptive heterogeneities and the generation of the dynamic compression stimuli. In absorptive heterogeneity testing, we reconstructed the absorption coefficients of transparent polypropylene tubing circulated with a skim milk-India ink mixture and embedded in a gel wax tissue simulating phantom. High linear correlations (R(2) greater than 0.989) were observed between the reconstructed and the measured absorption coefficients of the embedded tubing. In dynamic compression testing, five volunteer operators generated ten successive compression sessions by compressing the idNIRUS imager on a breast self examination wearable model following the computer simulated pressure profile. The manually generated pressure profiles demonstrated an accuracy of 95.7% and operator-dependent variation of less than 5%. The results of the current benchtop tests will help to optimize the most appropriate testing conditions for our future planned clinical trial.

Diagnostic imaging of oronasal fistulas in a dachshund.

Oronasal fistula development is described anecdotally as a common disease process in the dachshund but little is known about its imaging appearance. This case report describes the clinical presentation, computed tomography (CT) characterisation, dental radiograph confirmation and treatment of bilateral oronasal fistulas in a 14-year-old dachshund.

Antibiotic Irrigation of the Surgical Site Decreases Incidence of Surgical Site Infection after Open Ventral Hernia Repair.

Surgical site infections (SSI) are common complications after open ventral hernia repair (OVHR), potentially requiring further intervention. Antibiotic lavage before abdominal closure has been shown to lower the incidence in intra-abdominal and soft tissue SSI. A retrospective review of OVHR was performed with mesh at Greenville Health System Hernia Center between 2008 and 2017. Patients were divided into three groups, receiving no antibiotic irrigation (Grp 1, n = 260), gentamicin alone (Grp 2, n = 263), or gentamicin + clindamycin (G + C) irrigation (Grp 3, n = 299). Differences in categorical variables among the three groups were tested using chi-squared or Fischer's exact test (for n < 5). Analysis of continuous variables was performed using analysis of variance or Kruskal-Wallis test for differences in length of stay. Logistic regression was performed using all clinically relevant variables to determine the effects of irrigation on SSI. Incidence of surgical site occurrence was significantly lower after G + C irrigation (Grp 1, 28.1%; Grp 2, 35.4%; Grp 3, 19.7%; P < 0.001). Incidence of SSI was significantly lower after G + C irrigation, but not G alone (Grp 1, 16.5%; Grp 2, 15.2%; and Grp 3, 5.4%; P < 0.001). Multivariate logistic regression demonstrated significantly increased SSI with contaminated wounds (OR 2.96; 95% confidence interval (CI) 1.39-6.21), dirty wounds (OR 3.84; 95% CI 1.49-9.69), and chronic obstructive pulmonary disease (OR 3.70; 95% CI 2.16-6.38), as expected. Use of G + C was an independent predictor of decreased SSI (OR 0.33; 95% CI 0.16-0.67). Irrigation with a combined G + C antibiotic irrigation significantly reduces the incidence of surgical site infection after OVHR with mesh.

Association of transcription factor IIA with TATA binding protein is required for transcriptional activation of a subset of promoters and cell cycle progression in Saccharomyces cerevisiae.

The general transcription factor IIA (TFIIA) interacts with the TATA binding protein (TBP) and promoter DNA to mediate transcription activation in vitro. To determine if this interaction is generally required for activation of all class II genes in vivo, we have constructed substitution mutations in yeast TFIIA which compromise its ability to bind TBP. Substitution mutations in the small subunit of TFIIA (Toa2) at residue Y69 or W76 significantly impaired the ability of TFIIA to stimulate TBP-promoter binding in vitro. Gene replacement of wild-type TOA2 with a W76E or Y69A/W76A mutant was lethal in Saccharomyces cerevisiae, while the Y69F/W76F mutant exhibited extremely slow growth at 30 degrees C. Both the Y69A and W76A mutants were conditionally lethal at higher temperatures. Light microscopy indicated that viable toa2 mutant strains accumulate as equal-size dumbbells and multibudded clumps. Transcription of the cell cycle-regulatory genes CLB1, CLB2, CLN1, and CTS1 was significantly reduced in the toa2 mutant strains, while the noncycling genes PMA1 and ENO2 were only modestly affected, suggesting that these toa2 mutant alleles disrupt cell cycle progression. The differential effect of these toa2 mutants on gene transcription was examined for a number of other genes. toa2 mutant strains supported high levels of CUP1, PHO5, TRP3, and GAL1 gene activation, but the constitutive expression of DED1 was significantly reduced. Activator-induced start site expression for HIS3, GAL80, URA1, and URA3 promoters was defective in toa2 mutant strains, suggesting that the TFIIA-TBP complex is important for promoters which require an activator-dependent start site selection from constitutive to regulated expression. We present evidence to indicate that transcription defects in toa2 mutants can be both activator and promoter dependent. These results suggest that the association of TFIIA with TBP regulates activator-induced start site selection and cell cycle progression in S. cerevisiae.

Estimation of contrast agent concentration in intra- and extra-vascular spaces of brain tissue.

This article presents a new method for estimating the leakage of a contrast agent out of a vessel. The proposed method is developed based on tissue homogeneity (TH) model, modified Patlak model, and Monte Carlo simulation. The analytical methods published in the literature estimate the contrast agent leakage by solving the coupled differential equations associated with the TH model under adiabatic conditions. These methods employ unrealistic simplifying assumptions and become intractable in their applications to the vessels that have a non-uniform permeability. Without making any unrealistic assumptions, our approach simply tracks the passage of the contrast agent through the capillary and its crossing of the vessel walls based on the blood flow in the vessel, the vessel's permeability, and the condition of the blood-brain barrier (BBB). These are treated as statistical processes that can be modeled reasonably well using the Monte Carlo method. In the proposed approach, the intra- and extra-vascular spaces are divided into multiple compartments, similar to the Patlak model. A real, measured arterial input function (AIF) is used as the capillary input and the concentration of the contrast agent is found as a function of time and distance, inside and outside of the capillary. This is done for normal and abnormal capillaries with uniform and non-uniform permeability. The proposed method generates concentration curves similar to those of the analytical method for simple AIF models. It also generates reasonable concentration curves for a real AIF. The proposed method does not fit a mathematical function to the measured AIF and does not make unrealistic simplifying assumptions. It is not therefore prone to the fitting errors and generates more realistic and more accurate results than the analytical methods.

Toxic epidermal necrolysis and concurrent granulomatosis with polyangiitis (Wegener's granulomatosis). Management of a rare case and review of the literature.

Toxic epidermal necrolysis (TEN) is a rare, acute life-threatening mucocutaneous disorder that is characterised by epidermal loss/exfoliation exceeding 30% total body surface area (TBSA) and is on a spectrum that includes erythema multiforme and Stevens-Johnson syndrome (SJS). It is estimated that 80% of TEN cases are related to medication reactions; the association based on the recognition that TEN usually develops 1-3 weeks following administration of the suspect drug. It is agreed that primary treatment consists of prompt withdrawal of causative drugs and transfer to a regional burn unit. Transfer to a burn unit, no more than 7 days after onset of symptoms, has been acknowledged as reducing the risk of infections, hospital length of stay and infection-related mortality. Due to the uncertainty surrounding TEN pathogenesis, several different modalities have been proposed for the treatment of TEN, including high-dose intravenous immunoglobulins, plasmapheresis, cyclophosphamide, cyclosporine and systemic steroids; however, these therapies are relatively ineffective. The use of systemic corticosteroids for treatment of TEN has in particular been deemed controversial due to associations with increased infections leading to greater length of hospital stay and increased mortality. Granulomatosis with polyangiitis (GPA), formerly known as Wegener's granulomatosis, is a rare relapsing-remitting disorder of unknown aetiology, characterised by granulomatosis inflammation and necrotising vasculitis predominantly affecting small- to medium-sized vessels. While a 5-year survival rate of 75-83% is now realised, relapse and associated morbidity is of concern. The established treatment for GPA follows the recommendations of the French National Authority for Health (HAS) for systematic necrotising vasculitis. With induction treatment, it is recommended that GPA be treated with a combination of systemic corticosteroids and immunosuppressants. A review of the literature failed to identify any previous case where both of these conditions coincide. Our search was conducted through databases which included MEDLINE, PubMed, Scopus, AMED, CINAHL and EMBASE, using keywords: toxic epidermal necrolysis, Wegener's granulomatosis, granulomatosis with polyangiitis. We submit the rare case of a 22-year-old woman who presented to our regional burn unit with both GPA and TEN, and we discuss the presentation, investigation and multidisciplinary management of the patient, as well as reviewing the literature regarding these two conditions.

Donor CD31 genotype and its association with acute graft-versus-host disease in HLA identical sibling stem cell transplantation.

CD31 gene polymorphisms are implicated in the pathogenesis of graft-versus-host disease (GvHD) following haematopoietic stem cell transplantation (HST). We investigated the influence of CD31 genotype on the incidence of GvHD following HST from an human leukocyte antigen (HLA)-identical sibling donor. Donor and recipient CD31 codons 125, 563 and 670 DNA polymorphisms were determined in 85 cases of HLA identical sibling HST from two transplant centres. A correlation between CD31 genotype and acute GvHD was considered significant if observed in patients from both transplant centres independently. A strong correlation was identified between donor CD31 codon 125 genotype and the incidence of acute GvHD. Acute GvHD grades II-IV occurred in 27 of 46 (59%) recipients with a CD31 codon 125 leucine / valine heterozygous donor compared to nine of 39 (23%) recipients with a CD31 codon 125 homozygous donor (P=0.0019, relative-risk 2.45, 95% confidence interval 1.3-4.5). This correlation was significant in patients from both transplant centres (P=0.015 and P=0.019). We suggest that CD31 genotype may influence the function of donor-derived leukocytes and may be informative when there is a choice of comparable donors.

Distribution of constitutive (HO-2) and heat-inducible (HO-1) heme oxygenase isozymes in rat testes: HO-2 displays stage-specific expression in germ cells.

The heme oxygenase isozymes, HO-1 and HO-2, oxidatively cleave the heme molecule to produce antioxidants, the bile pigments, the gaseous cellular messenger, CO, and iron, a regulator of transferrin, ferritin, and nitric oxide synthase gene expression. HO-1 (hsp32) is a stress-inducible enzyme, whereas HO-2 is constitutively expressed at high levels in the testes and brain. In the present study, using immunohistochemical and in situ hybridization techniques, we report for the first time the cellular distribution of HO-1 and HO-2 in the testes of normal and heat-shocked rats and define a cell-specific expression of the isozymes and a stage-specific expression of HO-2 in the organ. In normal tissue, HO-1 was present at low levels in the Sertoli cells and could not be detected in germ or Leydig cells. HO-2, on the other hand, was most prominently expressed in residual bodies and was not detected in spermatogonia. Modest levels of HO-2 were observed in spermatocytes, spermatids, and select Leydig cells. In contrast, prominent expression of HO-2 messenger RNAs (mRNAs) was detected by in situ hybridization in spermatogonia, as well as spermatocytes, spermatids, and residual bodies of the seminiferous epithelium. The expression pattern of HO-2 protein and transcript in testes of heat-stressed (42 C; 20 min) rats did not differ from that in the control animals, whereas the expression pattern of HO-1 differed from that in the controls, in which distinct populations of Leydig and Sertoli cells displayed intense immunoreactivity. Thermal stress also resulted in an increase (2.8-fold) in the testicular HO-1 mRNA level within 1 h after treatment, followed by a significant increase (32%) in total microsomal heme oxygenase activity 6 h after treatment. Notably, this increase followed a significant depression (36%) in enzyme activity, which was detected 1 h after hyperthermia. The disparity between HO-2 mRNA and protein distribution clearly indicates cell-specific differences in the translational efficiency of HO-2 transcripts. It appears that HO-2 mRNA translation is linked to the maturation and expression of a factor(s) that regulates this process. This, in turn, appears to coincide with sperm development. HO-1 activity, on the other hand, which has a transcriptional component to its regulation, may have a role in maintenance of the conditions required for spermatogenesis.

Multiple molecular weight forms of immunoreactive alpha-inhibin in human seminal plasma.

The purpose of these studies was to determine whether the total immunoreactive alpha-inhibin protein concentration in seminal plasma correlated with serum gonadotropin levels or semen characteristics and to identify the forms of alpha-inhibin present in seminal plasma. Thirty-eight serum samples from men being evaluated for infertility were selected for study based on their serum hormone profiles and semen parameters. Serum LH and testosterone levels were normal, but FSH levels ranged from normal to hypergonadotropic (> 20 IU/L). Most semen parameters were within normal ranges, but germ cell numbers ranged from normal to azoospermic. Thus, seminal plasma from these men provided a unique opportunity to examine the antigenic forms of alpha-inhibin in individuals in whom strong correlations between inhibin and FSH levels might be predicted because of the observed ranges of FSH levels and germ cell numbers. Seminal plasma alpha-inhibin was characterized by RIA or Western blotting, using an antiserum directed against the N-terminal of the alpha-subunit of mature [32,000 mol wt (M(r))] inhibin. The antiserum recognized the alpha-subunit of dimeric inhibin as well as free alpha-inhibin and alpha-inhibin precursor proteins. Total immunoreactive alpha-inhibin ranged from 8.21-43.99 nmol/L in seminal plasma. However, alpha-inhibin levels were not statistically correlated with serum FSH levels or any of the measured semen parameters (including germ cell number). In contrast, the immunoreactive alpha-inhibin concentration in seminal plasma was negatively correlated (P < 0.01) with the serum LH level. Western blot analyses revealed that multiple forms of immunoreactive alpha-inhibin are present in seminal plasma. The majority of immunoreactivity was associated with monomeric proteins (ranging from 58,000-95,000 M(r)) that were larger than the alpha-subunit (21,000 M(r)) predicted for mature dimeric human inhibin (32,000 M(r)). The relative amounts of individual forms of immunoreactive alpha-inhibin varied among the patients studied, but could not be correlated with other serum or seminal parameters measured. Our observations demonstrate that various monomeric alpha-inhibin proteins are present in human seminal plasma. It is unlikely that these proteins alone or combined with inhibin beta-subunit proteins have identical biological activities. Thus, until assays specific for each of the various forms of immunoreactive alpha-inhibin are developed, their role as well as that of inhibin in the endocrine or local modulation of testicular function cannot be deduced from RIA data alone.