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Biomedical subjects

G M Penn

Publications and source records attributed to G M Penn.

14 recordsLinked to original sources
PubMed1991

Use of immunoglobulin heavy-chain and light-chain measurements in a multicenter trial to investigate monoclonal components: I. Detection.

We assessed the combined use of serum protein electrophoresis (SPE) and nephelometric measurement of immunoglobulin heavy- and light-chain components for detecting serum monoclonal immunoglobulins (monoclonal components, MC) in 4788 unselected samples from 4173 patients. MC were detected in 514 samples from 390 patients. In 356 these were detected by SPE; the other 34 had a normal SPE pattern but an abnormal kappa:lambda light-chain ratio (KLR). Only 208 of the 356 (58%) samples with bands by SPE had abnormal KLRs. Samples with MC concentrations greater than 5 g/L had a higher proportion of abnormal KLRs (75%) than those with concentrations less than 5 g/L (42%). The KLR was abnormal in 13% of samples in which no MC were visible by SPE or immunofixation electrophoresis (IFE). Compared with quantitative measurements of immunoglobulin heavy and light chains, high-quality SPE remains the method of choice for the detection of MC. Quantitative methods, however, are able to detect additional MC, especially those containing free light chains, and in the absence of SPE and IFE will detect about 75% of MC present at greater than 5 g/L.

Antibodies, Monoclonal↗
PubMed1990

Nd:YAG laser and photodynamic therapy for esophageal and endobronchial tumors under general and local anesthesia. Effects on arterial blood gas levels.

STUDY OBJECTIVE: Our objective was to determine the respiratory and acid-base metabolism response to endoscopic laser surgery for obstructive tumors, as related to the duration and different types of endoscopy, anesthesia, and laser treatment. DESIGN: The design was a case-control, cohort analytic, nonrandomized controlled survey of case series before and after endoscopic procedures. SETTING: A referral-based surgery and oncology practice at one hospital's laser center. PATIENTS: We studied a sequential sample of 82 patients in the age range from 35 to 92 years, with malignant and benign, primary and metastatic, partially and completely obstructing esophageal (15 patients) and endobronchial (67 patients) tumors. INTERVENTIONS: A total of 229 diagnostic, laser treatment, and follow-up endoscopic procedures was performed under general or local anesthesia (46 esophagoscopies and 183 bronchoscopies). The latter group consisted of 29 cases of general and 154 cases of local topical anesthesia. The last group involved 37 diagnostic and toilet bronchoscopies, 86 cases of YAG-laser tumor ablation, and 31 cases of PDT. MEASUREMENTS AND MAIN RESULTS: Direct-reading electrode measurements of arterial blood, sampled before and immediately after the endoscopic procedure, revealed statistically significant (p less than 0.001) increases in PaCO2 (200 of 229 cases) and decreases in pH (195 of 229 cases) and PaO2 (215 of 229 cases). These findings were similar after bronchoscopy and esophagoscopy, general and local anesthesia (only the decrease in pH was less pronounced in the latter case), and explorative endoscopies and different laser treatments and did not correlate with the total duration of the procedure within the wide time range of 7 to 210 minutes. The initial preoperative level of PaCO2 was considerably higher and the level of PaO2 was significantly lower in patients with endobronchial tumors, as compared to patients with esophageal cancer. A strong, inverse linear relationship was found between the perioperative changes in PaO2 and its initial level and between PaCO2 and pH changes. CONCLUSIONS: The PDT for esophageal and endobronchial malignancies is no more harmful for acid-base metabolism and respiratory functions than YAG-laser tumor ablation or any other common, nonlaser endoscopic procedure.

Adult↗
PubMed1982

Thymic changes in histiocytosis.

In order to arrive at a hypothesis of the pathogenesis of thymic changes in histiocytosis, the thymus glands from thirty-two children with histiocytosis were studied. In general, the changes were a severe loss of cortical and medullary structures rather than stress type changes in which only the cortical structure changes. The thymic changes were then classified into three main groups: severe dysplasia equivalent to that seen in congenital immune deficiency, severe nonspecific involution, and a third group designated as a dysmorphic type which resembled those with dysplasia, but, in addition, showed smaller lobules and interstitial histiocytic infiltration. The thymic changes correlated with the type of histiocytic disease. For the purposes of this study, the disease was categorized as Type I or Type II, as previously described. Dysplastic changes were only seen in those patients with Type I histiocytic disease, while involution occurred in patients with Type II histiocytic disease. Dysmorphic change was apparent in both, but it had a much higher incidence in Type II.

Child↗
PubMed1979

Selective IgA deviciency in Charcot-Marie-Tooth disease.

A selective IgA deficiency was found in five of 15 random patients with Charcot-Marie-Tooth disease. Immunologic studies of 32 members of the five families showed low IgA in 17 of the members, associated with elevated IgM in 20, without other significant immune abnormalities. The immunoglobulin pattern and the variability of symptoms in this familial peripheral neuropathy suggest that a thymic or gut-associated immune deficiency or both, may be causally related to the disease process.

Adolescent↗
PubMed1970

Genetic variants of G4 globulin. A unique relationship to other classes of G globulin.

Two types of gammaG4 proteins, termed 4a and 4b, were characterized through antigenic studies of myeloma proteins. Both were recognized by specific antigens on the Fc fragment which were shared with other gammaG classes. The distinctive antigen of the common 4a type was shared with all gammaG1 and gammaG3 proteins but missing in those of the gammaG2 class; that for the rarer 4b type was selectively found in proteins of the gammaG2 class. Analyses on gammaG4 fractions isolated from normal sera showed that either the 4a or the 4b or a mixture of the two types was present in each serum. Evidence was obtained that these differences were on a genetic basis and that allelic genes linked to those of the Gm system were involved. Such a reciprocal occurrence in other classes of gammaG globulin of the antigenic markers distinguishing genetic variants has not been observed previously. A number of questions regarding the evolutionary development of the genes responsible are discussed. The possibility is raised that those for the gammaG4 class arose relatively early and preceded the development of those for the other gammaG classes.

Antibody Specificity↗
PubMedDate not supplied

Angio-proliferative lesions in a homosexual boar with features resembling Kaposi's sarcoma.

Clinical, biopsy and necropsy studies of a homosexual boar revealed angio-proliferative lesions in the skin of the thigh, scrotum and the inguinal lymph node. Angiofibromas were identified in the dermis and subcutis of the thorax and mandible. The avidin-biotin-peroxidase complex technique demonstrated Factor VIII-related antigen as a marker for the neoplastic endothelial cells of the tumors. This boar also showed weight loss and lymphopenia. Explants of tumors were maintained in cultures for 22 passages and cultured cells produced tumors when injected subcutaneously into nude mice. No viral antigen was detected in the cultured tumor cells. Similarities and differences between the lesions in the boar and human Kaposi's sarcoma are discussed.

Animals↗
PubMedDate not supplied

Psychosocial modifiers of immunocompetence in medical students.

This study addressed the effects of a naturally occurring stressor on components of the immune response. Blood was drawn twice from 75 first-year medical students, with a baseline sample taken one month before their final examinations and a stress sample drawn on the first day of final examinations. Median splits on scores from the Holmes--Rahe Social Readjustment Rating Scale and the UCLA Loneliness Scale produced a 2 X 2 X 2 repeated measures ANOVA when combined with the trials variable. Natural killer (NK) cell activity declined significantly from the first to the second sample. High scorers on stressful life events and loneliness had significantly lower levels of NK activity. Total plasma IgA increased significantly from the first to second sample, while plasma IgG and IgM, C-reactive protein, and salivary IgA did not change significantly.

Adult↗