Ovomucoid domains: preparation and physico-chemical characterization

Four fragments of ovomucoid representing its individual domains and their different combinations were prepared by peptic and cyanogen bromide cleavages of the protein. The fragments corresponding to domains I + II, II + III, I and III of the parent ovomucoid molecule, were found to be homogeneous by gel filtration and polyacrylamide gel electrophoresis in presence and absence of SDS. Various physico-chemical properties of these proteins, such as molecular weight, NH2- and COOH-terminal amino acid residues, sugar content, isoionic pH, specific extinction coefficient, fluorescence emission spectra, intrinsic viscosity, frictional coefficient, Stokes radius, diffusion coefficient and geometrical mean radius were determined. Analysis of the results on trypsin inhibitory activity of ovomucoid and its different fragments suggested that only domain II is involved in the antitryptic activity of the inhibitor. Optical characteristics of these fragments indicate that they are devoid of tryptophan residues. The hydrodynamic properties suggest that intact ovomucoid and two of its fragments (domain I + II and domain II + III) are significantly different from those of typical globular proteins and are asymmetric in nature. However, the shape of the two remaining fragments representing domains I and III of the intact protein appeared to be compact and globular. Furthermore, domain II of ovomucoid has been suggested to primarily contribute towards the apparent asymmetry in the intact protein.

Diabetic microangiopathy in KK mice. VI. Effect of glycemic control on renal glycoprotein metabolism and established glomerulosclerosis

Twenty-three nonobese KK mice with abnormal tolerance to glucose, hyperinsulinemia with insulin resistance and human diabetic-like nephropathy were treated with either saline (12 mice) or glipizide, an oral hypoglycemic compound, 1 mg/kg, (11 mice) from 120 to 360 days of age. These mice develop significant increases in mesangial volume and matrix by 40 days of age. Oral glucose tolerance (OGTT), glucosyltransferase and N-acetyl-beta-glucosaminidase (enzymes involved in synthesis and degradation of kidney glycoproteins, respectively) in the kidney and serum, 24-hr proteinuria, and light microscopy studies of the kidney were performed. Glipizide-treated mice improved their OGTT. There was no difference in body weight; however, a 16% decrease (P less than 0.05) in kidney weight was observed in glipizide-treated mice. Both enzymes were significantly increased in the kidneys of mice treated with glipizide. No difference in serum enzymes was found between the two groups of mice. About 58% of the saline-treated mice had moderate glomerulosclerosis. By contrast, only 27% of glipizide-treated mice had moderate glomerulosclerosis. Also, a significant decrease in proteinuria was found in glipizide-treated mice. These data suggest that glipizide improves glucose metabolism, decreases kidney size, prevents kidney glycoprotein and mesangial matrix accumulation, and reduces proteinuria in type II diabetic KK mice. This indicates that good glycemic control prevents further progression of established diabetic nephropathy in animals.

An assay for heparin by decrease in color yield (DECOY) of a protein-dye-binding reaction

The interference by heparin and some related molecules with the well-known Bradford dye-binding assay for proteins is used as the basis of a rapid, sensitive method for the quantitation of these polysaccharides. Whereas the available methods for the assay of glycosaminoglycans have lacked specificity for sulfated polyanions in general and for heparin in particular, the procedure described here distinguishes among different uronic acid derivatives and, when performed in conjunction with heparinase digestion or cetylpyridinium chloride precipitation, can be used to determine heparin content of complex biological samples.

The relationship between new cardiac conduction defects and extension of valve infection in native valve endocarditis

New conduction defects in the setting of native valve infective endocarditis (IE) are commonly believed to be associated with direct extension beyond the free valve area. At University Hospital in Newark, among 100 cases of IE, in none of five instances of associated conduction defects (excluding first-degree heart block) was this the case. In neither of two instances of direct extension of valve infection was this accompanied by a new conduction defect. To explore this relationship, autopsy, surgical, and echocardiographic findings from other institutions were combined with these data. Among 47 instances of new conduction defects in IE, only 60% could be related to direct extension of valve infection. The cause was coronary embolization in 4% and unknown in 36%. Among 119 cases of complicated valve lesions, significant conduction defects were documented by ECG in only 15%. In IE the appearance of new conduction abnormalities may often result from causes other than extension of valve infection. Furthermore, complicated valve lesions may often be present without electrocardiographic evidence, indicating interruption of normal conduction pathways.

Dermatobia hominis myiasis masquerading as an infected sebaceous cyst

In an apparently routine case, what appeared to be infected sebaceous cysts of the scalp turned out to harbour botfly larvae imported from a tropical country. Although the parasite Dermatobia hominis is not indigenous to the United States, cutaneous myiasis caused by the fly is fairly common in Central and South America, and several cases have been reported in people returning or emigrating from these regions. The authors therefore suggest that infection resulting from D. hominis invasion be considered in persons who present with furuncular lesions and give a history of travel to endemic areas.

New outlook on pericardial substitution after open heart operations

The difficulties of reoperation owing to adhesions are well known. Clinical attempts to solve this problem using synthetic materials or glutaraldehyde-fixed pericardial xenograft have been less than satisfactory. Although experimental animal results have been good, they have not considered the influence of cardiopulmonary bypass (CPB) on adhesion formation. This study addressed the influence of CPB on the formation of adhesions and evaluated biodegradable polyglycolic acid as a material to reduce adhesions and as a pericardial substitute. Forty-five weanling sheep received implants of pericardial xenograft and polyglycolic acid with and without CPB. The pericardial xenograft showed no adhesions when implanted without CPB, but severe adhesions formed and a thick fibrinous layer covered the heart when CPB was used, making identification of coronary arteries at reoperation very difficult. The polyglycolic acid mesh implanted without CPB was absorbed and replaced with newly formed host collagen. With CPB, the polyglycolic acid was more rapidly absorbed, and a thinner layer of host collagen formed. Therefore, future animal studies must include CPB. In agreement with reported clinical results, glutaraldehyde-fixed pericardial tissue implanted with CPB resulted in severe epicardial reaction and therefore is not an ideal pericardial substitute.

Comparative in vitro activities of ofloxacin, difloxacin, ciprofloxacin, and other selected antimicrobial agents against Brucella melitensis

The in vitro activities of three quinolones (ofloxacin, difloxacin, and ciprofloxacin) were compared with those of trimethoprim-sulfamethoxazole, streptomycin, tetracycline, and rifampin against 47 Brucella melitensis strains. Ofloxacin was the most active of the test antimicrobial agents. It inhibited 90% of B. melitensis strains at a concentration of 0.02 micrograms/ml.

Immune deficiency with polymorphic reticulosis

A case of fatal polymorphic reticulosis, currently considered to be a peripheral T cell lymphoma, that was initially seen as a nasolabial swelling with a left lower lobe pulmonary nodule in a 40-year-old woman is reported. At autopsy, it was found to be associated with disseminated cryptococcosis and Pneumocystis carinii pneumonia associated with secondary severe immunodeficiency of unknown origin.

Aggravation of diabetic nephropathy by lithium: a case report and review of the literature

A manic-depressive diabetic man receiving lithium carbonate therapy had massive proteinuria, which dramatically improved after the withdrawal of lithium. The authors discuss previous cases of lithium-induced nephrotic syndrome in nondiabetics and draw attention to the possibility that lithium therapy aggravates protein excretion in diabetic patients.

On the origin of the positive band in the far-ultraviolet circular dichroic spectrum of fibronectin

The genesis of the positive bands in the far-ultraviolet circular dichroic spectra of human plasma fibronectin and its 31-kDa NH2-terminal heparin-binding fragment was studied. Spectra of ester derivatives of tyrosine, tryptophan, and phenylalanine and of model mixtures of these derivatives in which they are present in the same ratios as in the proteins indicate that all the aromatic side chains make substantial contributions to composite positive bands with maxima several nanometers below those of the proteins. In the presence of solvent perturbants such as polyethylene glycol and ethylene glycol, the bands of the model mixtures are red-shifted to the approximate positions they have in the spectra of the proteins. No additional red shift is seen with solvent perturbation of the proteins, suggesting that the conditions leading to this effect are satisfied within the proteins. A separate effect of solvent perturbation, an increase in amplitude of the positive band, occurs equally in solutions of free aromatic amino acid derivatives and in the proteins. This effect is used to estimate the relative accessibility of the chromophores of fibronectin and its fragment to different perturbants. The possible influence of protein secondary structure on the amplitude of the positive circular dichroic band is discussed.

Adenosquamous-cell carcinoma of the ovary: report of a case with positive peritoneal fluid cytology

Cytologic examination of peritoneal fluid showed only malignant squamous cells, without revealing adenocarcinomatous cell components, in a patient who had an endometrioid adenosquamous-cell carcinoma of the ovary. Histologic examination of the ovary demonstrated diffuse squamous-cell carcinoma with rare foci of endometrioid and abortive malignant glands, as well as isolated mucin-positive cells. The cytologic differential diagnosis of malignant squamous cells in peritoneal fluid and the pathogenesis of squamous-cell carcinoma of the ovary are discussed.

Brucellosis in Saudi Arabia

This paper describes the history of brucellosis and the current public health picture in the Kingdom of Saudi Arabia. Health protection is made more difficult by several factors: (a) the local custom of drinking raw and warm milk of sheep, goats, and camels, (b) the animal reservoir of infection in the country complicated by importation of live animals both for sacrifice during Haj periods and to increase commercial flocks, and (c) by uncontrolled movements of humans and stock across political borders.

Brucellosis in Saudi Arabia

This paper describes the history of brucellosis and the current public health picture in the Kingdom of Saudi Arabia. Health protection is made more difficult by several factors: (a) the local custom of drinking raw and warm milk of sheep, goats, and camels, (b) the animal reservoir of infection in the country complicated by importation of live animals both for sacrifice during Haj periods and to increase commercial flocks, and (c) by uncontrolled movements of humans and stock across political borders.

A probable mechanism of inactivation by urea of goat spleen cathepsin B. Unfolding and refolding studies

Equilibrium and kinetic studies of the unfolding-refolding of goat spleen cathepsin B induced by urea are reported. Tryptophan fluorescence and enzyme activity were monitored. The activity of cathepsin B is lost reversibly at 1.2 M-urea. The enzyme unfolds in two main stages, having a stable intermediate (Y) between its native (N) and fully denatured (D) states. Enzyme activity and kinetic studies of these transitions indicate the existence of at least two intermediate forms (X1 and X2) between the N and Y states. The overall denaturation and renaturation scheme is thus suggested to be N in equilibrium with X1----X2 in equilibrium with Y in equilibrium with D. The multiplicity of the intermediate and fractional regaining of the activity up to a urea concentration of 2 M indicates the presence of multidomain structure in cathepsin B.

Structural changes in the NH2-terminal domain of fibronectin upon interaction with heparin. Relationship to matrix-driven translocation

The effects of heparin and various related polysaccharides on the circular dichroic spectra of fibronectin and its 31-kDa NH2-terminal tryptic fragment were studied. These effects were evaluated with respect to (i) spectral features of the native proteins that are sensitive to pH denaturation and breaking of disulfide bonds, (ii) sensitivity of spectral changes to Ca2+, and (iii) the fibronectin-dependent interfacial interaction known as "matrix-driven translocation." We found that native heparin causes an attenuation of the positive CD peak at 228 nm with both the intact protein and the fragment, and causes a small but reproducible red shift in the spectrum of the fragment. All of these changes are analogous to spectral changes seen with denaturation or reduction of the proteins. In contrast to the situation with the intact protein, the heparin-induced spectral changes in the fragment were abolished in the presence of 10 mM Ca2+. Desulfation of heparin lessened or destroyed its ability to induce these changes, and carboxymethylated heparin and dextran sulfate induced different kinds of spectral alterations. Fibronectin and heparin determinants required for the induction of the characteristic spectral shift of the NH2-terminal domain corresponded to those required for matrix-driven translocation, suggesting that the associated conformational change in fibronectin plays a role in this biophysical effect.

The acquired immunodeficiency syndrome in intravenous drug abusers and patients with a sexual risk: clinical and postmortem comparisons

Clinical and necropsy findings in 13 intravenous drug abusers who died of the acquired immunodeficiency syndrome (AIDS) were reviewed and compared with findings in eight patients who acquired the infection through sexual exposure, the most common mode of transmission in AIDS. No differences were found in lymphocyte counts or duration of survival, despite reports that the degree of immunosuppression in intravenous drug abusers with AIDS differs from that in homosexuals. Neoplasms were found in 25 per cent of patients with sexual risks, but not in any drug abusers (0 per cent). Two opportunistic infections (toxoplasmosis and cytomegalovirus pneumonia and esophagitis) were more common in the intravenous drug abuser group. Although cytomegalovirus has been associated with Kaposi's sarcoma, this association was not found in this study. The postmortem findings in both groups were otherwise similar.

Does cathepsin B play a role in intracellular protein degradation?

Some properties of cathepsin B from a hitherto unstudied source (goat spleen) have been reported. The activity of the enzyme was optimal at pH 6.8 and it was fairly stable between pH 4.0-7.0. The maximum activity was observed at 37 degrees C and the enzyme could withstand temperature shocks up to 40 degrees C for 20 min without any significant loss of activity. Gamma-irradiation of the enzyme led to an increase in its activity in the beginning (up to 10 Gy) followed by a gradual decrease to about half of its activity at 1200 Gy. The enzyme was most active at an ionic strength of 0.022 and lost its activity substantially as the ionic strength was raised above the optimum value. The preferred protein substrate for the enzyme was found to be casein. The enzyme also hydrolyzed hemoglobin and serum albumin, but to lesser extents. In contrast to prevailing opinion, it was concluded that cathepsin B can act for a limited period even at physiological temperature, pH, etc. before it is inactivated.

Analysis of 506 consecutive positive serologic tests for brucellosis in Saudi Arabia

Brucellosis is common in the central region of Saudi Arabia. The major clue to the diagnosis is serologic testing. In 3 years, over 500 positive patients who had a titer of 1:160 or more were identified. Brucella species was the single organism most commonly recovered in all blood cultures, being found in 24% of patients with cultures positive for pathogenic bacteria. The expected greater number of Brucella cultures with high initial recorded titer was confirmed; 31% of the positive high-titer group had positive Brucella cultures. Conclusive correlation was uncommon below the 1:640 titer. The lower titers were less useful as indicators of active disease in this population, in which many people appear to have persistent low antibody levels.

Urea-induced structural transformations in bovine serum albumin

Urea-induced unfolding of bovine serum albumin and one of its fragments containing domain II + III has been studied by difference spectral and fluorescence emission measurements. The unfolding-refolding curves of both the proteins showed the presence of at least one stable intermediate when the transition was monitored at 288 nm. The presence of the intermediate was not detectable at 293 nm where only tryptophan contributed towards the protein absorption. However, both the proteins did show the presence of intermediate when the denaturation was monitored fluorometrically. Since domain III of the albumin is devoid of tryptophan, it is concluded that the formation of intermediate in the unfolding-refolding transition of serum albumin involves (i) unfolding of domain III, (ii) minor structural transformations in domain II, and/or (iii) the separation of the sub-domains of domain III from each other.

Anomalous behaviour of cathepsin B: dependence of activity and stability on salt concentration

Effect of salt concentration on the activity and stability of cathepsin B from buffalo spleen has been investigated. Catheptic activity was maximal at a buffer concentration of 5.5 x 10(-3) M. The enzyme was, however, highly unstable at a salt concentration lower than 1.5 x 10(-2) M. The use of 0.02 M sodium phosphate buffer has been suggested for the assay of cathepsin B activity. For storage of the enzyme, however, a 0.1 M sodium phosphate or other buffer of equivalent ionic strength has been recommended.

Direct evidence for the involvement of domain III in the N-F transition of bovine serum albumin

The domain III of bovine serum albumin containing residues 377-582 of the protein sequence was isolated and its behaviour in acid solution was studied. The fragment was found to undergo structural transformations over the pH range 3.5-4.5 known to cause N-F transition in serum albumin. On the other hand, an albumin fragment that was devoid of domain III was unable to exhibit such a transition. These results were consistent with a mechanism where N-F transition involves the separation of domain III from the rest of the albumin starts at about pH 4.3 and is completed at pH 3.5.

Schick test survey in rural children of Jawan Block, District Aligarh, (U.P.), India

THE PRESENT study conducted in three villages of Jawan block, Aligarh, India on 576 children showed a higher immunity to diphtheria in the age group of 3 months to 5 years. 99.3% children studied were shick negative. Only 4 children below the age of 3 years (0.7%), showed the positive schick test. Each of the 4 children belonged to lower social classes of illiterate Hindu parents and were not previously immunised against diphtheria.