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Biomedical subjects

R S Malek

Publications and source records attributed to R S Malek.

At least 19 recordsLinked to original sources
PubMed1992

Laser treatment of premalignant and malignant squamous cell lesions of the penis.

Thirty men with biopsy-proven premalignant or malignant squamous cell lesions of the penis were treated. All had subclinical aceto-white lesions with histologic evidence for human papilloma virus infection. Nineteen patients had penile intraepithelial neoplasia (PIN I and II) and 11 had squamous cell carcinoma. Of these 11 patients, 6 had noninvasive penile intraepithelial neoplasia--carcinoma in situ (PIN III/Tis)--and 5 had invasive squamous cell carcinoma (4 stage T2 and 1 T3). All were treated with laser: CO2 was used for low-stage lesions, Nd:YAG was used alone or in combination with CO2 laser for more histologically advanced lesions, and KTP/532 was used in one patient with squamous cell carcinoma (Tis). Follow-up in 23 patients for up to 2 years showed that all but 1 (stage T3) remained free from penile malignancy. Appropriate laser therapy for all but deeply invasive (T3) tumors controls local disease, producing results that are clinically equal and cosmetically and functionally far superior to partial penectomy.

Adult↗
PubMed1992

Sustained, substantially increased concentration of prostate-specific antigen in the absence of prostatic malignant disease: an unusual clinical scenario.

A 60-year-old man had a persistent, marked increase in the serum concentration of prostate-specific antigen (more than 20 times the upper limit of the reference range) and no identifiable prostatic malignant involvement. To our knowledge, this is the first such case reported in the literature. Possible explanations for this increased value are described, and nonmalignant conditions that can increase serum concentrations of prostate-specific antigen are reviewed.

Antigens, Neoplasm↗
PubMed1991

Vesicoureteral reflux in the adult. V. Unilateral disease.

We studied 37 patients with primary unilateral vesicoureteral reflux to compare medical (17) and surgical (20) management. Medical management consisted of observation and antimicrobial therapy as needed. During followup (mean 84.6 months) none of the patients in either management group had a significant decrease in total renal function, worsening of hypertension or progression of stone disease. The surgically treated group had a higher incidence of pyelonephritis preoperatively (75% versus 13%) but during followup these infections developed in only 10% of the surgical patients and in 13% of the medically managed group. The primary indication for surgical correction of unilateral reflux in adults is a history of pyelonephritis in patients in whom antibiotic prophylaxis has been unsuccessful or in women of childbearing age.

Adolescent↗
PubMed1990

Primary malignant lymphoma of the bladder.

We treated 11 patients with primary malignant lymphoma of the bladder. The typical patient is a woman more than 50 years old who presents with urgency and frequency of micturition, and occasionally gross hematuria. Hydronephrosis is present in half of the patients and cystoscopy usually reveals a solid tumor. Partial cystectomy, when feasible, with or without radiotherapy and chemotherapy is the usual treatment modality. When localized to the bladder, malignant lymphoma has an over-all favorable prognosis.

Female↗
PubMed1979

Renal stone epidemiology: a 25-year study in Rochester, Minnesota.

There are no adequate studies of the incidence of urolithiasis in the United States, in spite of earlier claims that a "stone belt" exists in the southeastern section of the country. This report is the first description of the incidence and recurrence rates for symptomatic noninfected renal stones in a well-defined population. A total of 798 patients were enrolled in the study group, of whom 672 were incidence cases having had their first episode as documented residents of Rochester, Minnesota, between 1950 and the end of 1974. The annual age-adjusted incidence rate for females was stable over the 25-year study period at 36.0 per 100,000 population. That for males increased significantly (P less than 0.02) from 78.5 per 100,000 to 123.6 per 100,000. Recurrence calculations showed a high rate for both sexes in the first year, followed by lower but constant rates for all succeeding years.

Adult↗
PubMed1979

The effects of deuteration on the metabolism of halogenated anesthetics in the rat.

The authors studied the effects of substituting deuterium for hydrogen in several volatile anesthetics on their metabolism in the Fischer rat. Substitution of deuterium in the ethyl portion of methoxyflurane increased the metabolic production of fluoride ion by 19 per cent when administered at a concentration of 0.05 per cent. Total replacement of hydrogen by deuterium resulted in a 29 per cent decrease in the amount of fluoride produced, while deuteration of only the methoxyl group produced a 33 per cent decrease in fluoride produced. Deuteration of halothane resulted in a 15 or 26 per cent decrease in serum bromide at 0.75 per cent or 1.0 per cent, respectively. Deuteration in the ethyl portions of enflurane and two experimental agents, CF2HOCF2CFBrH and CF2HOCF2CCl2H resulted in 65, 76, and 29 per cent decreases in urinary fluoride, respectively. Anesthesia with deuterated chloroform at a concentration of 0.36 per cent produced a 35 per cent decrease in serum glutamic pyruvic transaminase (SGPT). It is concluded that deuteration of volatile anesthetics changes their metabolism, in most cases producing decreases in metabolism. This effect may lessen the organ toxicity believed to occur with some of these anesthetics.

Alanine Transaminase↗
PubMed1978

Xanthogranulomatous pyelonephritis: a critical analysis of 26 cases and of the literature.

Manifestations of xanthogranulomatous pyelonephritis in 26 patients closely mimicked those of neoplastic and other inflammatory renal parenchymal diseases. Middle-aged or older women were affected most often. Most patients presented with anemia, chronic febrile illness, a painful tender flank mass and recurrent urosepsis. Some features of nephrogenic hepatic dysfunction were present in 13 patients. Bacterial cultures of renal tissue were almost always positive but the spectrum differed considerably from that of the bladder urine. Urographically, a renal mass lesion was encountered in 62% of the patients, nephrolithiasis in 38% and a functionless kidney in 27%. Angiographically, none of the 4 mass lesions studied was distinguished from hypernephroma. Indeed, a correct preoperative diagnosis was made in only 1 instance. There were 3 stages of xanthogranulomatous pyelonephritis recognized. Treatment consisted of nephrectomy for diffuse or advanced stage disease or both (21 patients), excision of the diseased renal segment for localized and low stage disease (2 patients) and renal biopsy (3 patients). Xanthogranulomatous pyelonephritis did not recur but in some patients bacteriuria continued or hypertension developed.

Adolescent↗
PubMed1978

Urologic aspects of vesicoenteric fistulas.

The classic symptoms of pneumaturia and fecaluria were not present in many of 100 patients (male to female ratio of 2.4) with vesicoenteric fistulas who presented with fever, abdominal mass or cystitis. There was a urinary tract infection in 95 per cent of the patients studied but only 29 per cent had a mixed infection. Roentgenographic studies suggested a fistula in 18 to 35 per cent of those studied but cystoscopy was singularly the most successful diagnostic technique (79 per cent). Inflammatory bowel disease in 63 per cent and colorectal adenocarcinoma in 16 per cent were the most common etiologic factors. Bladder carcinoma was the cause in only 5 per cent. Treatment consisted of single or multistage surgical repair of fecal diversion in 95 operable patients, with gratifying results, and of expectant management in the 5 inoperable patients.

Adenocarcinoma↗
PubMed1977

Acute scrotal swelling in Henoch-Schönlein syndrome.

A review of the literature regarding scrotal swelling in Henoch-Schönlein purpura is compared with our own experience at the Mayo Clinic over the previous ten years. Of 59 boys seen with Henoch-Schönlein purpura, 9 were noted to have scrotal swelling, and in 4 the presentation was of sufficient severity to suggest torsion. Two of these 4 were managed conservatively, and spontaneous recovery resulted. Surgical exploration of the scrotum in the other 2 revealed evidence of vasculitis in both and the possibility of torsion of appendix epididymis in 1. In patients with Henoch-Schölein purpura and scrotal pain and swelling, a conservative approach with cautious observation appears justified.

Acute Disease↗
PubMed1977

Paratesticular rhabdomyosarcoma in childhood.

Ten boys with paratesticular embryonal rhabdomyosarcoma were treated in a 44-year period. Two prognostically distinct stages of the disease and appropriate treatments are described. Children with non-infiltrating tumors (stage IA) are curable (3 patients are alive and free of tumor after 8 to 44 years) and radical orchiectomy with adjunctive radiation or, preferably, chemotherapy is adequate for these patients. Conversely, in those children with infiltrative tumors retroperitoneal nodal metastases invariably develop. Early retroperitoneal lymphadenectomy with adjuvant radiation and multidrug cyclic chemotherapy is life-saving (3 are alive and free of tumor after 2 1/2 to 4 years). However, delayed recognition and treatment of retroperitoneal disease, despite agressive therapy, is frequently disappointing--2 of 4 patients died after 2 and 6 years; another, who had advanced disease, is lost to followup and also is presumed dead and 1 is alive and free of tumor after 6 1/2 years.

Adolescent↗
PubMed1977

Renal lithiasis: a practical approach.

Management of most patients with calculous disease has been less than ideal in the past. Too often therapeutic efforts were limited to symptomatic calculi. Stones were allowed to pass or were removed, metabolic studies were incomplete, victims were dismissed and forgotten, and prophylactic measures were negligible and usually confined to milk restriction and use of distilled water. More patients were crippled with and died of recurrent calculous disease, urinary infection and progressive renal insufficiency than from any other upper urinary tract abnormality. During the last decade the development of a renal stone clinic at this institution has allowed a nephrourologic approach to the management of urolithiasis. This account of classification, diagnosis and management of the various syndromes associated with urolithiasis is based on the experiences gained during the last decade with this common but ill-understood urologic problem.

Acidosis, Renal Tubular↗
PubMed1977

Management of ruptured posterior urethra in childhood.

Seven boys with fracture(s) of the bony pelvis and associated partial or complete rupture of the posterior urethra were managed by the time-honored technique of early suprapubic cystostomy and concomitant primary realignment of the urethra over a catheter. Of the 4 children who had a functionally significant urethral stricture 3 were cured within a few months by 1 or 2 simple urethral dilatations and 1 by subsequent transperineal lysis of the angulated urethra from its surrounding fibrous tissue. Followup data for 8 to 22 years (mean 14 years) indicate that all 7 patients void with an excellent stream and are continent, free of infection and potent. In fact, 3 of the 4 married boys have fathered children.

Adolescent↗
PubMed1977

Observations on the ultrastructure and genesis of urinary calculi.

Conventional and scanning electron microscopy of calcigerous renal calculi discloses typical concentric laminations, radial striations and microspherules. Random axial distribution of oxalate crystals and their coating by electron-dense matrix fibers with a definite parallel orientation and cross-linkages are evident. The biochemical relationship of uromucoid to matrix substance A is described. It is suggested that renal sialidase may convert the urinary uromucoid to matrix substance A, whose apatite-covered fibers may be responsible for epitaxial nucleation of some crystal systems. Our studies indicate that the intimate apatite-matrix relationship occurs in the human nephron, probably as an intracellular phenomenon. Subsequent extrusion of these mineralized complexes into the lumen of the nephron (intranephronic calculosis) may, in some instances, represent the initial microanatomic stage of renal calculogenesis.

Calcium Phosphates↗
PubMed1976

The stone-forming kidney: a study of functional differences between individual kidneys in idiopathic renal lithiasis.

The 24-hour urinary excretion of various electrolytes, as well as the glomerular filtration rate, renal plasma flow and maximal rate of tubular excretion of para-aminohippuric acid was measured in each kidney of 10 patients with idiopathic renal lithiasis. Results in hypercalciuric patients indicate that, in contrast to earlier views, actively stone-forming, normally functioning kidneys are normocalciuric but hypophosphaturic in comparison to their mates with inactive or no stone disease, which are hypercalciuric but normophosphaturic. Therefore, hypophosphaturia rather than hypercalciuria may be an important calculogenic factor in some patients.

Adult↗
PubMed1976

Spontaneous urinary extravasation.

The diagnosis and management of 12 patients with spontaneous non-traumatic urinary extravasation are described. It is important to distinguish extravasation of the fornical backflow type from that owing to frank rupture of the diseased renal pelvis. Most cases of the former variety are caused by calculous ureteral obstruction and can be managed conservatively. Surgical intervention is indicated for the latter variety (frank rupture) and is based on the requirements imposed by the patient's clinical condition, the persistence of obstruction or extravasation, or the presence of complications of extravasation such as urinoma or abscess.

Adult↗
PubMed1976

Observations on vesical diverticulum in childhood.

An operation was required in 78 children with vesical diverticula in the absence of bladder outlet obstruction. Virtually all diverticula were located in juxtaposition to the ureteral orifice and were associated with vesicoureteral reflux in all but 6 of 89 diverticulum-ureteral units. Upper tract changes were seen on excretory urography in 78 per cent of the refluxing units. The surgical procedure of choice was diverticulectomy and ureteroneocystostomy, which yielded a high degree of success. Diverticulectomy alone and vesical neck revision were rarely indicated.

Adolescent↗