Treatment of Oral Dysplasia

Oral epithelial dysplasia refers to a premalignant lesion of the oral cavity. The diagnosis of dysplasia is rendered via pathologic assessment of diseased tissue. There are many different premalignant conditions identified in the oral cavity. These include leukoplakias, erythroplakias, proliferative verrucous leukoplakia, oral submucosal fibrosis, actinic cheilitis, and lichen planus. This article will discuss these different conditions and how they are diagnosed. It will also review the treatment for these entities.

Ulcerative and Inflammatory Lesions of the Oral Mucosa

Ulcerated and inflammatory lesions of the oral mucosa are not rare. A detailed patient medical and social history including habits and abuses, as well as the duration, location, focality and presence, or lack of local and/or systemic symptoms is critical in establishing a proper diagnosis. This article discusses the clinical presentation, management, and histopathologic characteristics of a variety of ulcerative and inflammatory lesions seen in the oral cavity.

Orofacial sarcoidosis: report of three cases

Introduction: Sarcoidosis is a systemic non-caseating granulomatous disorder of unknown etiology that may affect multiple organ systems. Head and neck involvement can present in unusual and often nonspecific ways. Observations: We report three cases of sarcoidosis with orofacial manifestations: one African American patient with an existing diagnosis who presented with perioral cutaneous involvement by sarcoidosis, and two Caucasian patients with cases where the initial oral presentation – diffusely affected gingiva in one and intraosseous jaw involvement with resultant dental implant failure in the other – led to workup and establishment of the diagnosis of sarcoidosis. The patients were referred to rheumatology and dermatology for appropriate treatment. Conclusion: Although oral lesions of sarcoidosis are not common, they may be the first clinical manifestation of sarcoidosis. The practitioner should be aware of the possible manifestations and be able to formulate an informed clinical differential diagnosis.

Secretory Carcinoma of the Salivary Gland - Systematic Review of the Literature and Report of 2 Cases

PURPOSE

Secretory carcinoma (SC) of the salivary gland, formerly known as mammary analogue secretory carcinoma, is an uncommon and fairly newly described low grade malignant neoplasm of the salivary gland. Given the small number of cases reported in the literature to date, treatment guidelines are scarce. This study aimed to describe the clinical characteristics of SC, discuss prior management strategies, and provide recommendations for future treatment.

METHODS

We performed a systematic review of all the cases of SC reported in the literature since it was first recognized in 2010. Using Pubmed, Crossref, and Google Scholar, we identified all articles reporting cases of SC.

RESULTS

We identified 657 cases of SC in 109 articles. In addition, we provided 2 new cases, for a total of 659 cases in 110 articles. To our knowledge, this is the largest review of cases of SC in the literature to date. We summarized the clinical characteristics of SC, as well as the nodal status, clinical management, recurrence rate, and death rate.

CONCLUSIONS

SC occurs on average in middle age (with a large age range), presents most often initially as localized disease without metastasis, and has a low but not insignificant recurrence rate. Deaths have been reported. The generalized recommendations for treatment of SC are in line with those of other low-grade salivary gland malignancies.

Oral manifestations of COVID-2019-related multisystem inflammatory syndrome in children: a review of 47 pediatric patients

Background

Although much is still unknown about the full effects of COVID-19, literature from the early stages of the COVID-19 pandemic (spring and summer 2020) supports a postviral immunologic reaction resulting in a multisystem inflammatory syndrome in children (MIS-C). The purpose of this study was to report the rates of documented oral and oropharyngeal manifestations among these patients and to determine the association of these findings with other MIS-C symptoms.

Methods

The authors conducted a retrospective review of pediatric patients with COVID-19 who were admitted to the Morgan Stanley Children’s Hospital of NewYork-Presbyterian. Patients fulfilling the Centers for Disease Control and Prevention criteria for MIS-C were included in this study. The documented signs, symptoms, and laboratory values were collected and compared with the presence of oral or oropharyngeal findings.

Results

The mean (standard deviation) age of MIS-C patients was 9.0 (5.0) years (range, 1.3-20.0 years), and there was no obvious sex difference (51.1% male, 48.9% female). With respect to oral findings, 23 patients (48.9%) had red or swollen lips, whereas only 5 (10.6%) had a strawberry tongue. Oral or oropharyngeal findings were associated significantly with the presence of systemic rash (P = .04) and conjunctivitis (P = .02).

Conclusions

The presence of oral or oropharyngeal changes may be an early indicator of MIS-C and should be considered suggestive of MIS-C in the setting of COVID-19 infection.

Practical Implications

Dental care providers may play an integral role both in the early detection of oral manifestations of MIS-C and in the identification of oral lesions in hospitalized patients with confirmed MIS-C.

Oral Pseudomyogenic Hemangioendothelioma: Case Report and Review of the Literature

Pseduomyogenic hemangioendothelioma (PMH) is a vascular neoplasm of intermediate biological potential first described by Hornick and Fletcher (Am J Surg Pathol 35:190-201, 2011). Despite its initial categorization as a malignant entity, PMH often demonstrates an indolent behavior profile, and thus was classified as a rarely metastasizing endothelial neoplasm in the 2013 WHO Classification of Tumors of Soft Tissue and Bone. It is a tumor primarily of skin and soft tissue, with most reported cases involving the trunk or extremities. To date, only one case of PMH involving the oral cavity has been reported. Herein, we present a case of PMH involving the mandibular gingiva and vestibule of a 33-year-old female and discuss the salient features of this entity.

MicroRNA-based risk scoring system to identify early-stage oral squamous cell carcinoma patients at high-risk for cancer-specific mortality

Background

For early‐stage oral squamous cell carcinoma (OSCC), there is no existing risk‐stratification modality beyond conventional TNM staging system to identify patients at high risk for cancer‐specific mortality.

Methods

A total of 568 early‐stage OSCC patients who had surgery only and also with available 5‐year clinical outcomes data were identified. Signature microRNAs (miRNAs) were discovered using deep sequencing analysis and validated by qRT‐PCR. The final 5‐plex prognostic marker panel was utilized to generate a cancer‐specific mortality risk score using the multivariate Cox regression analyses. The prognostic markers were validated in the internal and external validation cohorts.

Results

The risk score from the 5‐plex marker panel consisting of miRNAs‐127‐3p, 4736, 655‐3p, TNM stage and histologic grading stratified patients into four risk categories. Compared to the low‐risk group, the high‐risk group had 23‐fold increased mortality risk (hazard ratio 23, 95% confidence interval 13‐42), with a median time‐to‐recurrence of 6 months and time‐to‐death of 11 months (vs >60 months for each among low‐risk patient; p < .001).

Conclusion

The miRNA‐based 5‐plex marker panel driven mortality risk score formula provides clinically practical and reliable measures to assess the prognosis of patients assigned to an early‐stage OSCC.

Vascular Compromise After Soft Tissue Facial Fillers: Case Report and Review of Current Treatment Protocols

The use of facial fillers for soft tissue augmentation is becoming a mainstream treatment modality for patients. Owing to the relative ease of administration, as well as the lucrative nature of such procedures, the number of providers offering facial fillers has been expanding. Although many adverse effects of facial fillers are minor and localized to the site of injection, 1 potential serious, albeit uncommon, adverse effect of facial filler treatment is avascular necrosis. In this article, we review soft tissue filler complications and describe the case of a 52-year-old female patient in whom vascular compromise developed after facial filler administration. In addition to reviewing complications and best practices for treatment management, we discuss anatomic considerations, present an overview of the most common filler materials, describe histologic changes with dermal fillers, and discuss litigation consequences with the use of these minimally invasive procedures. Although facial filler treatment is regarded as a minimally invasive and extremely safe procedure, it is not without complications. Avascular necrosis after soft tissue augmentation with facial fillers is exceedingly rare, with only a few cases reported in the literature, but practitioners who offer this procedure need to be well versed in treatment protocols.

Salivary gland anlage tumor: molecular profiling sheds light on a morphologic question

OBJECTIVE

Salivary gland anlage tumor (SGAT), previously described as a squamous proliferative lesion or "congenital pleomorphic adenoma," is a rare, benign entity that presents within the first months of life. It occurs almost exclusively in the nasopharynx or posterior nasal cavity and demonstrates a biphasic composition of epithelial and mesenchymal elements. Although the clinical and histologic features of SGAT are well described, its etiology remains poorly understood. SGAT is currently considered a hamartoma rather than a neoplasm, partly because of its benign behavior and lack of reported recurrence after treatment. However, investigators have not yet evaluated this concept by using genomic methods.

STUDY DESIGN

Here, we present 3 SGAT cases where we performed whole-exome sequencing.

RESULTS

Examination of sequence data, with specific attention to variants affecting 964 cancer-related genes, showed no plausible driver-type alterations.

CONCLUSIONS

The lack of apparent driver mutations supports the classification of this entity as a hamartomatous (nonneoplastic) process.

Characteristics and Prognosis of Primary Head and Neck Angiosarcomas: A Surveillance, Epidemiology, and End Results Program (SEER) Analysis of 1250 Cases

Head and neck angiosarcomas (HN-AS) are rare malignancies with a poor prognosis relative to other soft tissue sarcomas. To date, the HN-AS literature has been limited to short reports and single-institution experiences. This study evaluated patients registered with the Surveillance, Epidemiology, and End Results (SEER) program who had been diagnosed with a primary HN-AS. Predictors were drawn from demographic and baseline tumor characteristics. Outcomes were survival months and cause of death. Kaplan-Meier analyses were used to estimate overall (OS) and disease-specific survival (DSS) rates. Cox proportional hazards regression models were used for multivariate analyses. A total of 1250 patients (mean age 73.3 years) were identified, and nearly all lesions (93.5%) were cutaneous. Two- and 5-year OS rates were 47.3% (95% CI 44.3-50.3) and 26.5% (95% CI 23.7-29.3), while 2- and 5-year DSS rates were 66.6% (95% CI 63.6-69.6) and 48.3% (95% CI 44.5-52.1). In the univariate analyses, age, race, tumor grade, tumor size, AJCC stage, SEER historic stage, and surgery were significant predictors of both OS and DSS. Multivariate regression revealed that independent predictors of poor OS and DSS were older age [OS: HR 1.04 (95% CI 1.02-1.05), p < 0.01; DSS: HR 1.03 (95% CI 1.01-1.05), p < 0.01], increased tumor size [OS: HR 1.01 (95% CI 1.01-1.01), p < 0.01; DSS: HR 1.01 (95% CI 1.01-1.02), p < 0.01], and distant disease [OS: HR 2.97 (95% CI 1.65-5.34), p < 0.01; DSS: HR 4.99 (95% CI 2.50-9.98), p < 0.01]. Age, tumor size, and disease extent were determinants of HN-AS survival. When all other factors were controlled, lower histologic grade and surgery did not improve the risk of death.

Lingual cyst with respiratory epithelium: report of 2 cases and review of the literature

The lingual cyst with respiratory epithelium, a congenital cyst of the tongue or floor of the mouth, is lined predominately by respiratory-type epithelium. The terminology for this lesion was first proposed in 1999 by Manor et al., who stated that a descriptive term is best for this cyst of debatable pathogenesis. Although it is a cyst of foregut origin, the lingual cyst with respiratory epithelium is distinguished from the traditional enteric (foregut) duplication cyst in that the latter contains gastric and/or intestinal-type mucosa and has smooth muscle within the cyst wall. This article presents 2 new cases of this entity, as well as reviews the 19 cases that have been reported in the literature and were found to fulfill the histologic criteria of an lingual cyst with respiratory epithelium.

Renal cell carcinoma metastatic to the maxillary gingiva: A case report and review of the literature

Tumor metastasis to the oral cavity is rare and is usually an indication of late-stage disease and poor prognosis. While, there are reports of renal cell carcinoma (RCC) metastatic to oral cavity, vast majority of them are to the jaw. Herein, we present a case of a 78-year-old woman with RCC metastasis limited to the oral soft tissue without any bone involvement. As the lesion solely involved maxillary gingiva, it clinically mimicked that of a pyogenic granuloma, which is a reactive, nonneoplastic condition. This case was further complicated as the patient was unaware of primary cancer and appeared to be in good physical health. Her oral metastasis marked the initial manifestation of an otherwise silent primary renal cancer.

Mandibular embryonal rhabdomyosarcoma with cartilaginous metaplasia: report of a case and review of literature

Rhabdomyosarcoma (RMS) is a malignant tumor of skeletal muscle origin and frequently involves the head and neck region. It represents the second most common pediatric soft tissue sarcoma and accounts for 3% of all childhood cancers. Here, we report a case of embryonal RMS presenting as a right-sided facial swelling in a 7-year-old boy. Histologically, the tumor consisted of classic embryonal rhabdosarcomatous areas with metaplastic cartilage, in both initial biopsy and final resection specimens. Cartilaginous metaplasia arising in the background of RMS is a rare finding, thus raising a diagnostic challenge. To the best of our knowledge, this represents the first case of RMS with cartilaginous metaplasia in the oral cavity.

Alveolar soft part sarcoma metastatic to the mandible: A report and review of literature

Alveolar soft part sarcoma (ASPS) is a rare neoplasm constituting less than 1% of all soft tissue sarcomas. It tends to occur in the deep soft tissues of the lower extremities, however approximately 5-12% of cases are primary to the head and neck region. ASPS metastatic to the oral cavity is rare, with only four documented cases in the literature. Here, we present the case of a 29-year-old woman with ASPS metastatic to the mandible. To the best of our knowledge, this represents only the 5th documented case of ASPS metastatic to the oral cavity, and more specifically, the 3rd documented case of mandibular metastasis.

Streptococcus pasteurianus septicemia

Streptococcus pasteurianus is part of the normal flora of the intestine. It has also been isolated from various infection sites. However, to date it has not been reported as a cause of fulminant septicemia and death. We report the post-mortem findings in a splenectomized hemophiliac patient with cirrhosis and concurrent human immunodeficiency virus (HIV), hepatitis B and hepatitis C infections.

Screening and clinical management of prostate cancer. A cross-national comparison

OBJECTIVES

The objectives of the study were to identify the current standards of clinical practice regarding prostate cancer screening in western Europe, Canada, and the United States, and to highlight major characteristics of current prostate cancer screening programs or patterns of practice.

METHODS

We performed a semi-structured interview by means of a self-administered questionnaire sent by fax to 26 institutes pertaining to the International Network of Agencies for Health Technology Assessment.

RESULTS

None of the countries surveyed had a formal national screening policy. Despite that, all the countries answering the questionnaire had discretionary, public-financed screening practices. Moreover, some scientific and professional organizations recommended population screening for prostate cancer, and few of the surveyed countries offered it as experimental practice within a randomized controlled trial. Survey results showed variation regarding screening policies, in particular test of choice, age cut-off points, and treatment prescribed for positive test results.

CONCLUSIONS

Despite the lack of conclusive evidence on the benefits of prostate cancer screening, the availability of simple and easy-to-administer tests has lead to an enormous variation on screening policies around the world. Practice variations also affect prostate cancer therapy.

Enterobacterial repetitive intergenic consensus polymerase chain reaction typing of isolates of Enterobacter cloacae from an outbreak of infection in a neonatal intensive care unit

BACKGROUND

Enterobacter cloacae has become a common cause of nosocomial infections. This study was designed to investigate the pattern of spread of E cloacae during an outbreak in a neonatal intensive care unit.

METHODS

Enterobacterial repetitive intergenic consensus polymerase chain reaction was used to examine 111 E cloacae isolates from 17 patients, including 81 from surveillance cultures, 23 from endotracheal tubes, 3 from eyes, and 1 each from blood, urine, skin, and throat. Antibiotic susceptibility profiles were also obtained.

RESULTS

Infection with E cloacae resulted from endogenous bacteria and from horizontal transmission. One group of 61 isolates, a third of which were obtained from clinical specimens, was uniformly susceptible to imipenem and ciprofloxacin only. A second group of 50 isolates, only 18% of which were obtained from clinical specimens, was susceptible to all antibiotics tested except for aminopenicillins and first-generation cephalosporins.

CONCLUSION

These data indicate that (1) patient-to-patient spread is an important cause of E cloacae infection in the neonatal intensive care unit and (2) highly antibiotic-resistant E cloacae may emerge during an outbreak.

Clonal diversity of vancomycin-resistant enterococci from an outbreak in a tertiary care university hospital

BACKGROUND

Enterococci have become important nosocomial pathogens and now account for approximately 12% of nosocomial infections. Enterococci can be transferred from patient to patient and from health care personnel to patient. We investigated the clonal diversity of vancomycinresistant enterococci (VRE) causing an outbreak of infections and attempted to determine the patterns of spread of these bacteria in a university hospital.

METHODS

Ribotyping was used to examine the clonal diversity of 50 VRE isolates, including 23 from wounds, 14 from urine, 8 from blood, 3 from the rectum, 1 from drainage, and 1 from the cornea.

RESULTS

Nine patients were infected with Enterococcus faecalis, 10 with Enterococcus faecium, 3 with both E faecalis and E faecium, and 1 with Enterococcus avium. The results suggest that the sources of the VRE infections included endogenous strains and strains acquired by transmission from attending staff or from the environment. Three patients were infected by both nosocomial and endogenous strains.

CONCLUSIONS

These data suggest that the collection and analysis of several isolates from repeated specimens is necessary to obtain a fuller understanding of the epidemiology and population structure of antibiotic-resistant enterococci.

Effects of renal cytoprotective agents on erythrocyte membrane stability

To elucidate potential mechanisms of ischemic renal injury, investigators often use drugs that interfere with specific pathological pathways and study their protective efficacy in in vitro models of ischemia, such as isolated renal proximal tubules subjected to hypoxia. However, the protective effects of certain drugs may depend on non-specific membrane-stabilizing properties. We have studied the effects of several drugs on membrane integrity using osmotic lysis of erythrocytes as a model system. Freshly isolated rabbit erythrocytes were subjected to a hypotonic shock, and the protective effects of various calcium channel blockers, phospholipase inhibitors, free fatty acids, the NO-synthase inhibitor L-NAME, the amino acid glycine and its receptor-analogue strychnine, and two chloride channel blockers were examined. Most agents protected erythrocytes against hypotonic hemolysis when added to the medium in the same concentration range as used in suspensions of hypoxic proximal tubules. Only the protective agents that proposedly act via a blockade of chloride influx (glycine, strychnine and the chloride channel blockers), did not attenuate hypotonic hemolysis. The erythrocyte hemolysis assay may provide an easy and rapid method to screen for non-specific membrane-stabilizing effects of potentially cytoprotective agents.

Cold preservation of isolated rabbit proximal tubules induces radical-mediated cell injury

BACKGROUND

Reactive oxygen species (ROS) are involved in reperfusion injury after preservation. Recent studies in isolated endothelial cells and hepatocytes suggested the occurrence of ROS-mediated injury during the period of cold incubation. In the present study, formation of ROS and subsequent cell injury were studied in freshly isolated rabbit proximal tubules (PTs).

METHODS

PTs were incubated in University of Wisconsin (UW) solution, Euro-Collins solution, or a modified Krebs-Henseleit buffer under aerobic conditions for up to 94 hr at 4 degrees C. ROS formation and cell death were assessed as lipid peroxidation (formation of thiobarbituric acid-reactive substances [TBARS]) and release of lactate dehydrogenase, respectively. The involvement of ROS was further investigated in UW solution using compounds that might interfere with ROS formation. In addition, tubules were studied under anaerobic conditions (gassing with 95% N2/5% CO2).

RESULTS

Cold preservation of rabbit PTs in any of the solutions under aerobic conditions caused progressive lipid peroxidation and concomitant cell injury. Addition to UW solution of inhibitors of ROS formation, in particular 2,2'-dipyridyl, or removal of oxygen by gassing with 95% N2/5% CO2, prevented lipid peroxidation and protected rabbit PTs against cold injury. Both the nitric oxide (NO) synthase inhibitor L-NAME and dexamethasone, which blocks the inducible NO synthase, were ineffective. The cytoprotectant glycine affected neither TBARS formation nor lactate dehydrogenase release.

CONCLUSIONS

Cold preservation of renal PTs under aerobic conditions caused cell injury even in the specially designed preservation solution UW. Cell injury is caused by iron-dependent, NO synthase-independent ROS formation.

Hypoxia decreases calcium influx into rat proximal tubules

Renal ischemia results in adenosine triphosphate (ATP) depletion, particularly in cells of the proximal tubule (PT), which rely heavily on oxidative phosphorylation for energy supply. Lack of ATP leads to a disturbance in intracellular homeostasis of Na+, K+ and Cl-. Also, cytosolic Ca2+ levels in renal PTs may increase during hypoxia [1], presumably by a combination of impaired extrusion and enhanced influx [2]. However, Ca2+ influx was previously measured using radiolabeled Ca2+ and at varying partial oxygen tension [2]. We have now used to Mn2(+)-induced quenching of fura-2 fluorescence to study Ca2+ influx in individual rat PTs during normoxic and hypoxic superfusion. Normoxic Ca2+ influx was indeed reflected by the Mn2+ quenching of fura-2 fluorescence and this influx could be inhibited by the calcium entry blocker methoxyverapamil (D600; inhibition 50 +/- 2% and 35 +/- 3% for 10 and 100 mumol, respectively). La3+ completely blocked normoxic Ca2+ influx. Hypoxic superfusion or rat PTs did not induce an increase in Ca2+ influx, but reduced this influx to 79 +/- 3% of the normoxic control. We hypothesize that reducing Ca2+ influx during hypoxia provides the cell with a means to prevent cellular Ca2+ overload during ATP-depletion, where Ca2+ extrusion is limited.

Glycine protection against hypoxic injury in isolated rat proximal tubules: the role of proteases

BACKGROUND

Isolated rat proximal tubules are frequently used as a model to study hypoxic injury. Glycine is a very effective protective agent against hypoxia-induced cell injury in this model. The mechanisms involved in hypoxic renal injury and glycine protection are still debated. We have focused on the role of proteolytic enzymes.

METHODS

Isolated rat proximal tubules in suspension were gassed with either 95%O2/5%CO2 or 95%N2/5%CO2 to create normoxic or hypoxic conditions. Cell injury was assessed by the release of LDH. Activity of proteolytic enzymes was measured by quantifying the release of fluorescent 7-amino-4-methylcoumarin from specific substrates, which were added to tubules in suspension or to cytosolic fractions of permeabilized tubules.

RESULTS

Fifteen minutes of hypoxia caused cell injury, which was completely prevented by glycine. Activities of serine-, aspartate-, and the calcium-dependent cysteine protease calpain were increased in these hypoxic tubules in suspension, but only calpain activity was attenuated by glycine. Cytosolic fractions obtained by digitonin-permeabilization of hypoxic (15 min) tubules showed increased proteolytic activity of all measured classes of proteases and glycine prevented these increases. In measurements performed at an earlier time point (7.5 min) neither changes in calpain activity nor effects of glycine were detected. Calpain activity was not inhibited directly by glycine.

CONCLUSIONS

Hypoxia increases the activity of several classes of proteases. The effects of glycine on protease activation are equivocal, and may merely reflect the potential of glycine to prevent hypoxia-induced lethal membrane injury.

The effect of acrylic nails on the measurement of oxygen saturation as determined by pulse oximetry

Pulse oximetry (Spo2) is a simple, noninvasive method that is widely used to determine oxygen saturation in patients undergoing surgical procedures. Artificial acrylic nails have recently become fashionable to strengthen and lengthen nails. This study investigates the effect of unpolished acrylic nails on the measurement of oxygen saturation by pulse oximetry. Data were collected during a 3-month period. Thirty women, average age 32 years (range 18 to 61 years), were recruited at a high-volume nail salon in northwestern Pennsylvania. A baseline pulse oximetry reading was obtained on each subject's natural, unpolished fingernail using a Nellcor N-20/N-20P portable pulse oximeter (Nellcor Incorporated, Hayward, California). A licensed nail technician applied the acrylic compound to the same finger. After the compound had hardened in approximately 5 minutes, a second reading was obtained on the unpolished acrylic nail. The mean pulse oximetry reading at baseline was 97.33% and after acrylic nail application, 97.58%. Using a paired Student's t test, no statistically significant differences existed between readings. This study demonstrates that unpolished acrylic nails do not affect pulse oximetry measurements of oxygen saturation. Patients may not need to remove unpolished acrylic nails before surgery.

Rise in cytosolic Ca2+ and collapse of mitochondrial potential in anoxic, but not hypoxic, rat proximal tubules

It has been suggested that ischemic renal proximal tubular cell injury is mediated by an increase in cytosolic calcium concentrations ((Ca2+)i). However, measurements of (Ca2+)i in rat or rabbit proximal tubules exposed to hypoxia or anoxia have yielded ambiguous results. This study explored the possibility that the severity of oxygen deprivation and the energy state of the mitochondria are important determinants of (Ca2+)i. To this end, (Ca2+)i (measured with fura-2) and the mitochondrial membrane potential (measured with rhodamine 123) were studied simultaneously in individual rat proximal tubules in hypoxic and anoxic conditions. (Ca2+)i did not change during hypoxia, but increased rapidly during anoxia. Increases in (Ca2+)i were only observed in parallel with a decrease of rhodamine 123 fluorescence, which indicates a collapse of the mitochondrial membrane potential. The increase in (Ca2+)i during anoxia was prevented by incubating the tubules in a low Ca2+ medium, which did not interfere with the collapse of the mitochondrial membrane potential. Both hypoxic and anoxic incubation led to cell death, as assessed by the fluorescent dye propidium iodide. These results clearly demonstrate that the level of oxygen deprivation is critical in determining changes in (Ca2+)i. Because cell damage occurred in both hypoxic and anoxic conditions. It was concluded that an increase in (Ca2+)i is not a necessary prerequisite for the development of ischemic cell injury.

Protection against hypoxic injury of rat proximal tubules by felodipine via a calcium-independent mechanism

Most evidence for a key role of calcium entry in hypoxia-induced renal damage stems from studies with calcium channel blockers. In proximal tubules, a primary site of renal ischaemic injury, only phenyl-alkylamines, especially verapamil, have been studied. In the present study the effect of the dihydropyridine felodipine on hypoxic injury in isolated rat proximal tubules was investigated. To discriminate between the block of calcium entry and other effects, the enantiomers and a non-calcium blocking derivative of felodipine (H186/86) were included. Cell membrane injury was assessed by measuring the release of lactate dehydrogenase (LDH). At high concentrations (100 microM) felodipine, H186/86 and the two enantiomers all protected rat proximal tubules against hypoxia-induced injury to the same extent. Absence of extracellular calcium did not offer protection, but rather enhanced hypoxic injury. All dihydropyridines used increased the intracellular potassium concentration during normoxia. Felodipine attenuated the hypoxia-induced loss of cellular potassium. We have tried to mimic the effects of felodipine by using potassium channel blockers. The potassium channel blockers quinidine and glibenclamide afforded some protection against hypoxic injury, although their effects on cellular potassium were equivocal. We conclude that the dihydropyridine calcium channel blocker felodipine protects rat proximal tubules against hypoxic injury via a calcium-independent mechanism. We propose that high levels of intracellular potassium and attenuation of potassium loss during hypoxia are important in this protection.

Analysis of peripheral blood lymphocytes of AIDS and high-risk patients for human cytomegalovirus transforming DNA sequences

Investigation into the presence of human cytomegalovirus (HCMV) transforming mtrII and mtrIII sequences in peripheral blood lymphocyte (PBL) specimens of AIDS and high-risk patients was carried out by nucleic acid hybridization analyses. These probes were selected because they were viral-specific and lacked homology to normal cellular DNAs. In Southern blot hybridizations carried out under stringent conditions, we detected HCMV mtrII sequences associated with the high-molecular-weight DNAs of PBLs in 17 of 37 patients either with AIDS/Kaposi's sarcoma or at high risk for AIDS. In comparison, only 2 of 17 DNA specimens from PBLs of healthy blood donors showed hybridization to mtrII sequences. The inability to detect hybridization to the mtrIII region in most mtrII-positive specimens suggested a specific retention of mtrII sequences. Our study suggests that the retention of mtrII sequences in high molecular weight DNA may constitute a risk factor for the development/progression of AIDS. Alternatively, the retention of mtrII sequences may occur as a result of enhanced HCMV replication in patients with AIDS or at high risk for AIDS.

Lack of transmission of human immunodeficiency virus from infected children to their household contacts

The possibility of transmission of the human immunodeficiency virus (HIV) from infected children to their contacts has been confronted in households, schools, day-care centers, and other child care settings. Cases reported to the Centers for Disease Control and several studies of close contacts of HIV-infected patients suggested that the risk of transmission in these settings is extremely low. However, most of these studies involved infected adults or older children. Younger children, who drool, bite, mouth toys, and are incontinent, may be more likely to transmit HIV in these settings. To assess this possibility, the authors tested 89 members of households in which 25 children with HIV infection, most of whom were preschool-aged, resided. Household members had close personal contact with the infected children. They shared many items likely to be soiled with blood and body fluids, such as toys, toothbrushes, eating utensils, toilets, and bathtubs. Hugging, kissing, sharing a bed, and bathing together were common. Household members were tested no sooner than 4 months after initial contact with the infected child, to allow adequate time for sero-conversion. All 89 participating household members were anti-HIV seronegative, and 78 who were tested were serum p24 antigen negative. It was concluded from this study and other evidence that the risk of transmission from children to their contacts is extremely low and has not been clearly documented in the household setting.