Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya.

Sites in eastern Africa have shed light on the emergence and early evolution of the genus Homo. The best known early hominin species, H. habilis and H. erectus, have often been interpreted as time-successive segments of a single anagenetic evolutionary lineage. The case for this was strengthened by the discovery of small early Pleistocene hominin crania from Dmanisi in Georgia that apparently provide evidence of morphological continuity between the two taxa. Here we describe two new cranial fossils from the Koobi Fora Formation, east of Lake Turkana in Kenya, that have bearing on the relationship between species of early Homo. A partial maxilla assigned to H. habilis reliably demonstrates that this species survived until later than previously recognized, making an anagenetic relationship with H. erectus unlikely. The discovery of a particularly small calvaria of H. erectus indicates that this taxon overlapped in size with H. habilis, and may have shown marked sexual dimorphism. The new fossils confirm the distinctiveness of H. habilis and H. erectus, independently of overall cranial size, and suggest that these two early taxa were living broadly sympatrically in the same lake basin for almost half a million years.

New hominids from the Lake Turkana Basin, Kenya.

New hominid fossils from the Lake Turkana Basin range in age from ca. 3.35 to ca. 1.0 Ma. Those recovered from sediments stratigraphically just above the Tulu Bor Tuff in the Lomekwi Member of the Nachukui Formation are best attributed to Australopithecus afarensis. This species is rare in Kenya, probably because of the scarcity of sediments deposited during its time span. Younger specimens are referable either to the megadont A. boisei or early Homo. Collectively the new fossils promote further understanding of morphological variation in East African Plio-Pleistocene hominids.

New hominin genus from eastern Africa shows diverse middle Pliocene lineages.

Most interpretations of early hominin phylogeny recognize a single early to middle Pliocene ancestral lineage, best represented by Australopithecus afarensis, which gave rise to a radiation of taxa in the late Pliocene. Here we report on new fossils discovered west of Lake Turkana, Kenya, which differ markedly from those of contemporary A. afarensis, indicating that hominin taxonomic diversity extended back, well into the middle Pliocene. A 3.5 Myr-old cranium, showing a unique combination of derived facial and primitive neurocranial features, is assigned to a new genus of hominin. These findings point to an early diet-driven adaptive radiation, provide new insight on the association of hominin craniodental features, and have implications for our understanding of Plio-Pleistocene hominin phylogeny.

Differential diagnosis of the palatal mass.

It is well understood that the palatal mass can pose a difficult diagnostic dilemma for the clinician. The differential diagnosis of the palatal mass includes the palatal abscess, benign and malignant salivary gland neoplasms, the benign neural tumors, and the traumatic or irritation fibroma. The lesions have many characteristics in common and may appear clinically indistinguishable. Emphasis is placed on the importance of obtaining a thorough, comprehensive health and dental history and collecting relevant laboratory information. Ultimately, a biopsy of the palatal mass may be necessary to render a definitive diagnosis and determine the optimal treatment and management of the patient.

Pneumoparotitis with orthodontic treatment.

Self-induced pneumoparotitis has not been commonly associated with orthodontic treatment nor dental treatment in general. However, the patient described previously and the other reported cases demonstrate the distinct possibility that accommodation to appliance irritation by "puffing out" the cheeks could result in parotid swelling. Pneumoparotitis should definitely be considered in the evaluation of patients with parotid swelling, particularly in cases of unexplained swelling with rapid onset.

Pneumoparotitis associated with the use of an air-powder prophylaxis unit.

A case reporting barotrauma to the parotid gland secondarily to the use of an air-powder prophylaxis unit is presented. Air pressure associated with these units usually exceeds that for air/driven turbines or air/water dental syringes, yet the reported incidence of iatrogenic trauma is very low. Improper angulation in the use of these instruments may result in serious sequellae. Differential diagnosis and physical examination following trauma to the parotid is discussed.

The inter-rater reliability and internal consistency of a clinical evaluation exercise.

OBJECTIVE: To assess the internal consistency and inter-rater reliability of a clinical evaluation exercise (CEX) format that was designed to be easily utilized, but sufficiently detailed, to achieve uniform recording of the observed examination. DESIGN: A comparison of 128 CEXs conducted for 32 internal medicine interns by full-time faculty. This paper reports alpha coefficients as measures of internal consistency and several measures of inter-rater reliability. SETTING: A university internal medicine program. Observations were conducted at the end of the internship year. PARTICIPANTS: Participants were 32 interns and observers were 12 full-time faculty in the department of medicine. The entire intern group was chosen in order to optimize the spectrum of abilities represented. Patients used for the study were recruited by the chief resident from the inpatient medical service based on their ability and willingness to participate. INTERVENTION: Each intern was observed twice and there were two examiners during each CEX. The examiners were given a standardized preparation and used a format developed over five years of previous pilot studies. MEASUREMENTS AND MAIN RESULTS: The format appeared to have excellent internal consistency; alpha coefficients ranged from 0.79 to 0.99. However, multiple methods of determining inter-rater reliability yielded similar results; intraclass correlations ranged from 0.23 to 0.50 and generalizability coefficients from a low of 0.00 for the overall rating of the CEX to a high of 0.61 for the physical examination section. Transforming scores to eliminate rater effects and dichotomizing results into pass-fail did not appear to enhance the reliability results. CONCLUSIONS: Although the CEX is a valuable didactic tool, its psychometric properties preclude reliable assessment of clinical skills as a one-time observation.

An investigation of the relationship between self-report of memory functioning and memory test performance.

Memory complaints are some of the most common cognitive problems presented to clinical psychologists and neuropsychologists. However, the probable validity of memory complaints presented to a psychologist rarely has been validated by objective memory tests. Using the Memory Functioning Questionnaire (MFQ; Gilewski et al., 1983), 62 relatively young adults reported the extent to which they were experiencing various types of memory problems. These data were compared with findings of memory and non-memory tests on an expanded Halstead-Reitan test battery and with the MMPI/MMPI-2. Results showed that with the exception of persons with more than one MMPI/MMPI-2 evaluation, memory complaints were not related more to memory than to non-memory tests.

Smoker's melanosis. A case report.

Smoker's melanosis is a benign pigmentation of the oral mucosa, predominantly observed on the attached anterior mandibular gingiva and interdental papillae. These macular lesions are independent of genetic factors, therapeutic medication usage, and various systemic disorders. As a group they are often seen after the third decade of life. Due to the onset in adulthood and the progressive darkening, malignant melanoma must be ruled out. A review of the literature and a case report of this interesting and unique entity is presented.

Differential diagnosis of localized tumors of the gingiva.

Localized tumors arising from the periodontal structures are commonly seen in the oral cavity. Although not a daily occurrence, these tumors will probably be encountered by all practitioners during their professional lives. The majority of localized tumors arising from the periodontal structures are benign, but early recognition and treatment are imperative to prevent invasion and destruction of the surrounding structures.

Histologic survey of the frena of the oral cavity.

The literature shows an apparent lack of agreement concerning the histologic morphology of the frena of the oral cavity, particularly relating to the presence or absence of skeletal or striated muscle. The purpose of this study was to do a histologic retrospective analysis of 40 oral frenal biopsy specimens. The results of the study showed that approximately 37.5% of the frena investigated contained skeletal or striated muscle.

The effect of air abrasive polishing on blood pH and electrolyte concentrations in healthy mongrel dogs.

The recent re-emergence of air abrasive polishing as an adjunct to professional tooth cleaning has been accompanied by a substantial amount of research. Most of this research has focused on the efficacy of the Prophy-Jet and similar devices in the removal of plaque and stain and on the effects of such devices on restorative materials and the various hard structures of the tooth. Little attention has been paid to the effects of mucosal absorption of the sodium bicarbonate in the polishing abrasive. The purpose of this study was to measure any changes in arterial blood chemistry resulting from the use of the Prophy-Jet. The values for pH, sodium, and bicarbonate, as well as other electrolytes, were measured in 10 dogs over a 2 hour period following a 5 minute timed use of the Prophy-Jet. Of all the parameters examined, only the potassium concentration showed a statistically significant change, and the magnitude of this change was not felt to be clinically significant. The pH and concentrations of sodium and bicarbonate remained essentially unchanged with the use of the Prophy-Jet.

A rationale for management of the dentogingival junction.

The proper placement of cervical margins is a difficult and demanding procedure. The use of a sulcular landmark can be a useful guide for correct tooth preparation.

Management of root-amputated maxillary molar teeth: periodontal and prosthetic considerations.

Recent studies have shown that maxillary molar teeth with furcation involvement can be retained for many years in a state of health. Removal of one or more roots may be required to create a morphology that can be maintained. Proper treatment planning is essential for long-term success. The indications for root amputation and surgical technique are described. Esthetic restorative procedures are illustrated.

Stratigraphic context of fossil hominids from the Omo group deposits: northern Turkana Basin, Kenya and Ethiopia.

The chronometric framework developed for Plio-Pleistocene deposits of the northern Turkana Basin is reviewed in light of recent advances in lithostratigraphy, geochemical correlation, paleomagnetic stratigraphy, and isotopic dating. The sequence is tightly controlled by 20 precise ages on volcanic materials. These ages are internally consistent but are at variance with estimates for the boundaries of the magnetic polarity time scale by about 0.07 my. This discrepancy can be only partially resolved at present. Based on the established chronometric framework and stratigraphic sequences, depositional ages can be estimated for significant marker beds. These ages can in turn be used to constrain the 449 hominid specimens thus far reported from the basin. Ages for most hominid specimens can be estimated with a precision of +/- 0.05 my. In addition, the chronometric framework will be applicable to other paleontological collections, archeological excavations, and future discoveries in the basin.

Erythema multiforme following cardizem therapy: report of a case.

A 63-year-old male developed severe, painful ulcerations shortly after beginning therapy for angina with diltiazem (Cardizem). Erythema multiforme is a common adverse reaction to medications. The case report, as well as the role of the dentist in diagnosis and management of these clinical presentations, is discussed.