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Biomedical subjects

M Mauro

Publications and source records attributed to M Mauro.

14 recordsLinked to original sources

Synthetic guinea pig insulin B-chain C-terminal decapeptide: a novel immunogen for generating immunocytochemical-grade antisera.

Antisera to guinea pig insulin are not commonly available, largely because of the short supply and limited immunogenicity of the intact hormone. To overcome these problems we have employed a novel reagent, synthetic guinea pig insulin B-chain C-terminal decapeptide, as a hapten for raising antibodies that react with intact guinea pig insulin. The decapeptide, coupled to bovine serum albumin, was successfully used as an immunogen in rabbits. The resulting anti-serum was employed for immunocytochemical staining of guinea pig insulin in pancreatic sections. The specificity of the staining was verified by both pre-absorption and pre-immune serum controls. The utility of this new antiserum for investigations of guinea pig insulin physiology is discussed.

Amino Acid Sequence

[Inguinal hernioplasty after Shouldice].

The authors review their two-year experience of hernioplasty using a modified version of Shouldice's technique which includes the employment of a polyglyconate monofilament. Although the series of patients is chronologically limited, the findings appear to confirm that this is a valid alternative to other techniques proposed to date for treating inguinal hernia.

Abdominal Muscles

X-ray structures of recombinant yeast cytochrome c peroxidase and three heme-cleft mutants prepared by site-directed mutagenesis.

The 2.2-A X-ray structure for CCP(MI), a plasmid-encoded form of Saccharomyces cerevisiae cytochrome c peroxidase (CCP) expressed in Escherichia coli [Fishel, L.A., Villafranca, J. E., Mauro, J. M., & Kraut, J. (1987) Biochemistry 26, 351-360], has been solved, together with the structures of three specifically designed single-site heme-cleft mutants. The structure of CCP(MI) was solved by using molecular replacement methods, since its crystals grow differently from the crystals of CCP isolated from bakers' yeast used previously for structural solution. Small distal-side differences between CCP(MI) and bakers' yeast CCP are observed, presumably due to a strain-specific Thr-53----Ile substitution in CCP(MI). A Trp-51----Phe mutant remains pentacoordinated and exhibits only minor distal structural adjustments. The observation of a vacant sixth coordination site in this structure differs from the results of solution resonance Raman studies, which predict hexacoordinated high-spin iron [Smulevich, G., Mauro, J.M., Fishel, L. A., English, A. M., Kraut, J., & Spiro, T. G. (1988) Biochemistry 27, 5477-5485]. The coordination behavior of this W51F mutant is apparently altered in the presence of a precipitating agent, 30% 2-methyl-2,4-pentanediol. A proximal Trp-191----Phe mutant that has substantially diminished enzyme activity and altered magnetic properties [Mauro, J. M., Fishel, L. F., Hazzard, J. T., Meyer, T. E., Tollin, G., Cusanovich, M. A., & Kraut, J. (1988) Biochemistry 27, 6243-6256] accommodates the substitution by allowing the side chain of Phe-191, together with the segment of backbone to which it is attached, to move toward the heme. This relatively large (ca. 1 A) local perturbation is accompanied by numerous small adjustments resulting in a slight overall compression of the enzyme's proximal domain; however, the iron coordination sphere is essentially unchanged. This structure rules out a major alteration in protein conformation as a reason for the dramatically decreased activity of the W191F mutant. Changing proximal Asp-235 to Asn results in two significant localized structural changes. First, the heme iron moves toward the porphyrin plane, and distal water 595 now clearly resides in the iron coordination sphere at a distance of 2.0 A. The observation of hexacoordinated iron for the D235N mutant is in accord with previous resonance Raman results. Second, the indole side chain of Trp-191 has flipped over as a result of the mutation; the tryptophan N epsilon takes part in a new hydrogen bond with the backbone carbonyl oxygen of Leu-177.(ABSTRACT TRUNCATED AT 400 WORDS)

Binding Sites

Biliary diversion for pancreatic carcinoma: matching the methods and the patient.

Two hundred eleven patients with adenocarcinoma of the pancreas were reviewed. Seventy had surgically constructed biliary-enteric anastomoses. Forty-two had percutaneous/endoscopic placement of biliary diversion catheters. Surgical biliary diversion was associated with discharge at 7 +/- 2 days postoperatively. Only five patients required subsequent reoperations for anastomotic failure secondary to continued tumor growth. Sixty-one percent of percutaneous/endoscopic catheters were associated with septicemia, and 27% occluded (average life span 36 days). Hospital days averaged 20 days of an average 64-day patient life span. After evaluation of computed tomographic scans and surgical findings, patients' diseases were arbitrarily divided into (A) local, (B) regional, and (C) distant spread. Survival was 417,300, and 53 days, respectively. In view of the morbidity associated with the percutaneous/endoscopic catheter, we recommend that its use be restricted to Group C patients.

Adenocarcinoma

Antihypertensive and renal effects of tertatolol, a new beta-blocking agent, in hypertensive patients.

Tertatolol, a new nonselective beta-adrenoceptor blocker, was administered to 11 hypertensive patients in a short-term study. Systolic and diastolic blood pressure and heart rate were significantly decreased when compared to the placebo period: in spite of that glomerular filtration rate and renal plasma flow were unchanged. The administration of metoclopramide (a dopaminergic receptor antagonist) caused a significant reduction of renal plasma flow and a significant rise of renal vascular resistances during placebo, but no change during tertatolol therapy. A possible interference of tertatolol on dopaminergic receptors is discussed as the mechanism responsible for the unmodified renal plasma flow despite the significant blood pressure lowering with tertatolol.

Adrenergic beta-Antagonists

CT features of intraabdominal abscesses: prediction of successful percutaneous drainage.

Fifty-three patients with 71 intraabdominal abscesses identified on computed tomography (CT) and treated with percutaneous abscess drainage were evaluated for the possible predictive value of any particular CT feature in relation to the outcome of percutaneous drainage. Features analyzed included the presence of a "rind," sharp exterior margin, air-fluid level, scattered internal gas bubbles, and internal septations, as well as size, site, and the presence or absence of fistulas as determined by sinography. Statistical analysis revealed that only site has predictive value; liver and subphrenic abscesses were more likely to have a successful outcome than abscesses in other locations (84% vs 47% complete cure). The presence of a long air-fluid level denoted communication with the gastrointestinal tract, which led to significantly longer drainage times and larger drainage volumes. Since there are no CT features that can strongly predict a poor outcome, all intraabdominal abscesses should be considered candidates for percutaneous drainage.

Abdomen